diff --git a/jscomp/bsb/bsb_file_groups.ml b/jscomp/bsb/bsb_file_groups.ml
index 03a234a65b..dac20e07c6 100644
--- a/jscomp/bsb/bsb_file_groups.ml
+++ b/jscomp/bsb/bsb_file_groups.ml
@@ -38,7 +38,7 @@ type file_group = {
   is_dev : bool;
   generators : build_generator list;
       (* output of [generators] should be added to [sources],
-         if it is [.ml,.mli,.re,.rei]
+         if it is [.ml,.mli,.res,.resi]
       *)
 }
 
diff --git a/jscomp/bsb/bsb_file_groups.mli b/jscomp/bsb/bsb_file_groups.mli
index fc0176bded..6abc224941 100644
--- a/jscomp/bsb/bsb_file_groups.mli
+++ b/jscomp/bsb/bsb_file_groups.mli
@@ -39,7 +39,7 @@ type file_group = {
   (* false means not in dev mode *)
   generators : build_generator list;
       (* output of [generators] should be added to [sources],
-         if it is [.ml,.mli,.re,.rei]
+         if it is [.ml,.mli,.res,.resi]
       *)
 }
 
diff --git a/jscomp/gentype/EmitJs.ml b/jscomp/gentype/EmitJs.ml
index 8a939ff3af..a61b0e16f0 100644
--- a/jscomp/gentype/EmitJs.ml
+++ b/jscomp/gentype/EmitJs.ml
@@ -229,7 +229,7 @@ let emitCodeItem ~config ~emitters ~moduleItemsEmitter ~env ~fileName
                ("In case of type error, check the type of '" ^ valueName
               ^ "' in '"
                ^ (fileName |> ModuleName.toString)
-               ^ ".re'" ^ " and '"
+               ^ ".res'" ^ " and '"
                ^ (importPath |> ImportPath.emit)
                ^ "'.")
              ~early:true ~emitters ~name:valueNameTypeChecked ~type_
diff --git a/jscomp/gentype/GenTypeMain.ml b/jscomp/gentype/GenTypeMain.ml
index 65b3de03f6..1184778246 100644
--- a/jscomp/gentype/GenTypeMain.ml
+++ b/jscomp/gentype/GenTypeMain.ml
@@ -104,9 +104,9 @@ let processCmtFile cmt =
     let isInterface = Filename.check_suffix cmtFile ".cmti" in
     let resolver =
       ModuleResolver.createLazyResolver ~config
-        ~extensions:[ ".re"; ".res"; EmitType.shimExtension ]
+        ~extensions:[ ".res"; EmitType.shimExtension ]
         ~excludeFile:(fun fname ->
-          fname = "React.re" || fname = "ReasonReact.re")
+          fname = "React.res" || fname = "ReasonReact.res")
     in
     let inputCMT, hasGenTypeAnnotations =
       let inputCMT = readCmt cmtFile in
diff --git a/jscomp/gentype/ModuleResolver.ml b/jscomp/gentype/ModuleResolver.ml
index 53106049d5..a54da792e0 100644
--- a/jscomp/gentype/ModuleResolver.ml
+++ b/jscomp/gentype/ModuleResolver.ml
@@ -195,20 +195,17 @@ let apply ~resolver ~useBsDependencies moduleName =
   moduleName |> Lazy.force resolver.lazyFind ~useBsDependencies
 
 (** Resolve a reference to ModuleName, and produce a path suitable for require.
-   E.g. require "../foo/bar/ModuleName.ext" where ext is ".re" or ".js". *)
+   E.g. require "../foo/bar/ModuleName.ext" where ext is ".res" or ".js". *)
 let resolveModule ~(config : Config.t) ~importExtension ~outputFileRelative
     ~resolver ~useBsDependencies moduleName =
   let outputFileRelativeDir =
-    (* e.g. src if we're generating src/File.re.js *)
+    (* e.g. src if we're generating src/File.bs.js *)
     Filename.dirname outputFileRelative
   in
   let outputFileAbsoluteDir = config.projectRoot +++ outputFileRelativeDir in
-  let moduleNameReFile =
-    (* Check if the module is in the same directory as the file being generated.
-       So if e.g. project_root/src/ModuleName.re exists. *)
-    outputFileAbsoluteDir +++ (ModuleName.toString moduleName ^ ".re")
-  in
   let moduleNameResFile =
+    (* Check if the module is in the same directory as the file being generated.
+       So if e.g. project_root/src/ModuleName.res exists. *)
     outputFileAbsoluteDir +++ (ModuleName.toString moduleName ^ ".res")
   in
   let candidate =
@@ -216,7 +213,7 @@ let resolveModule ~(config : Config.t) ~importExtension ~outputFileRelative
     moduleName
     |> ImportPath.fromModule ~dir:Filename.current_dir_name ~importExtension
   in
-  if Sys.file_exists moduleNameReFile || Sys.file_exists moduleNameResFile then
+  if Sys.file_exists moduleNameResFile then
     candidate
   else
     let rec pathToList path =
@@ -229,7 +226,7 @@ let resolveModule ~(config : Config.t) ~importExtension ~outputFileRelative
     match moduleName |> apply ~resolver ~useBsDependencies with
     | None -> candidate
     | Some (resolvedModuleDir, case, bsDependencies) ->
-        (* e.g. "dst" in case of dst/ModuleName.re  *)
+        (* e.g. "dst" in case of dst/ModuleName.res *)
         let walkUpOutputDir =
           outputFileRelativeDir |> pathToList
           |> List.map (fun _ -> Filename.parent_dir_name)
diff --git a/jscomp/gentype/Paths.ml b/jscomp/gentype/Paths.ml
index 32b1881dc2..16b57ee4e1 100644
--- a/jscomp/gentype/Paths.ml
+++ b/jscomp/gentype/Paths.ml
@@ -61,7 +61,7 @@ let getBsConfigFile ~projectRoot =
   match bsconfig |> Sys.file_exists with true -> Some bsconfig | false -> None
 
 (** Find the relative path from /.../bs/lib
-   e.g. /foo/bar/bs/lib/src/Hello.re --> src/Hello.re *)
+   e.g. /foo/bar/bs/lib/src/Hello.res --> src/Hello.res *)
 let relativePathFromBsLib fileName =
   if Filename.is_relative fileName then fileName
   else
diff --git a/jscomp/gentype_tests/typescript-react-example/src/IgnoreInterface.resi b/jscomp/gentype_tests/typescript-react-example/src/IgnoreInterface.resi
index 9c7b72b9c6..7a7cf64707 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/IgnoreInterface.resi
+++ b/jscomp/gentype_tests/typescript-react-example/src/IgnoreInterface.resi
@@ -1,4 +1,4 @@
-// Use the annotations, and definitions, from the .re file
+// Use the annotations, and definitions, from the .res file
 @@genType.ignoreInterface
 
 @genType type t
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.gen.tsx b/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.gen.tsx
index 8e81e77f70..53527ec0de 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.gen.tsx
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.gen.tsx
@@ -6,7 +6,7 @@ import {default as makeNotChecked} from './hookExample';
 
 import {default as defaultNotChecked} from './hookExample';
 
-// In case of type error, check the type of 'make' in 'ImportHookDefault.re' and './hookExample'.
+// In case of type error, check the type of 'make' in 'ImportHookDefault.res' and './hookExample'.
 export const makeTypeChecked: React.ComponentType<{
   readonly person: person; 
   readonly children: React.ReactNode; 
@@ -20,7 +20,7 @@ export const make: unknown = makeTypeChecked as React.ComponentType<{
   readonly renderMe: ImportHooks_renderMe<string>
 }>;
 
-// In case of type error, check the type of 'default' in 'ImportHookDefault.re' and './hookExample'.
+// In case of type error, check the type of 'default' in 'ImportHookDefault.res' and './hookExample'.
 export const defaultTypeChecked: React.ComponentType<{
   readonly person: person; 
   readonly children: React.ReactNode; 
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.gen.tsx b/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.gen.tsx
index 627a68e112..0ffc03894d 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.gen.tsx
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.gen.tsx
@@ -6,7 +6,7 @@ import {makeRenamed as makeRenamedNotChecked} from './hookExample';
 
 import {foo as fooNotChecked} from './hookExample';
 
-// In case of type error, check the type of 'makeRenamed' in 'ImportHooks.re' and './hookExample'.
+// In case of type error, check the type of 'makeRenamed' in 'ImportHooks.res' and './hookExample'.
 export const makeRenamedTypeChecked: React.ComponentType<{
   readonly actions?: JSX.Element; 
   readonly person: person; 
@@ -22,7 +22,7 @@ export const makeRenamed: unknown = makeRenamedTypeChecked as React.ComponentTyp
   readonly renderMe: renderMe<any>
 }>;
 
-// In case of type error, check the type of 'foo' in 'ImportHooks.re' and './hookExample'.
+// In case of type error, check the type of 'foo' in 'ImportHooks.res' and './hookExample'.
 export const fooTypeChecked: (_1:{ readonly person: person }) => string = fooNotChecked;
 
 // Export 'foo' early to allow circular import from the '.bs.js' file.
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.gen.tsx b/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.gen.tsx
index d0e0fdca0c..be5656abba 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.gen.tsx
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.gen.tsx
@@ -4,7 +4,7 @@
 
 import {default as defaultNotChecked} from './';
 
-// In case of type error, check the type of 'default' in 'ImportIndex.re' and './'.
+// In case of type error, check the type of 'default' in 'ImportIndex.res' and './'.
 export const defaultTypeChecked: React.ComponentType<{ readonly method?: "push" | "replace" }> = defaultNotChecked;
 
 // Export '$$default' early to allow circular import from the '.bs.js' file.
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.gen.tsx b/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.gen.tsx
index 205508536a..4963838083 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.gen.tsx
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.gen.tsx
@@ -22,31 +22,31 @@ import {default as defaultNotChecked} from './MyMath';
 import * as Curry__Es6Import from 'rescript/lib/es6/curry.js';
 const Curry: any = Curry__Es6Import;
 
-// In case of type error, check the type of 'round' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'round' in 'ImportJsValue.res' and './MyMath'.
 export const roundTypeChecked: (_1:number) => number = roundNotChecked;
 
 // Export 'round' early to allow circular import from the '.bs.js' file.
 export const round: unknown = roundTypeChecked as (_1:number) => number;
 
-// In case of type error, check the type of 'area' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'area' in 'ImportJsValue.res' and './MyMath'.
 export const areaTypeChecked: (_1:point) => number = areaNotChecked;
 
 // Export 'area' early to allow circular import from the '.bs.js' file.
 export const area: unknown = areaTypeChecked as (_1:point) => number;
 
-// In case of type error, check the type of 'returnMixedArray' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'returnMixedArray' in 'ImportJsValue.res' and './MyMath'.
 export const returnMixedArrayTypeChecked: () => numberOrString[] = returnMixedArrayNotChecked;
 
 // Export 'returnMixedArray' early to allow circular import from the '.bs.js' file.
 export const returnMixedArray: unknown = returnMixedArrayTypeChecked as () => numberOrString[];
 
-// In case of type error, check the type of 'useColor' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'useColor' in 'ImportJsValue.res' and './MyMath'.
 export const useColorTypeChecked: (_1:color) => number = useColorNotChecked;
 
 // Export 'useColor' early to allow circular import from the '.bs.js' file.
 export const useColor: unknown = useColorTypeChecked as (_1:color) => number;
 
-// In case of type error, check the type of 'higherOrder' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'higherOrder' in 'ImportJsValue.res' and './MyMath'.
 export const higherOrderTypeChecked: (_1:((_1:number, _2:number) => number)) => number = higherOrderNotChecked;
 
 // Export 'higherOrder' early to allow circular import from the '.bs.js' file.
@@ -58,7 +58,7 @@ export const higherOrder: unknown = function (Arg1: any) {
   return result
 } as (_1:((_1:number, _2:number) => number)) => number;
 
-// In case of type error, check the type of 'convertVariant' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'convertVariant' in 'ImportJsValue.res' and './MyMath'.
 export const convertVariantTypeChecked: (_1:variant) => variant = convertVariantNotChecked;
 
 // Export 'convertVariant' early to allow circular import from the '.bs.js' file.
@@ -71,13 +71,13 @@ export const convertVariant: unknown = function (Arg1: any) {
     : {TAG: 1, _0:result.value} as any
 } as (_1:variant) => variant;
 
-// In case of type error, check the type of 'polymorphic' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'polymorphic' in 'ImportJsValue.res' and './MyMath'.
 export const polymorphicTypeChecked: <a>(_1:a) => a = polymorphicNotChecked;
 
 // Export 'polymorphic' early to allow circular import from the '.bs.js' file.
 export const polymorphic: unknown = polymorphicTypeChecked as <a>(_1:a) => a;
 
-// In case of type error, check the type of 'default' in 'ImportJsValue.re' and './MyMath'.
+// In case of type error, check the type of 'default' in 'ImportJsValue.res' and './MyMath'.
 export const defaultTypeChecked: number = defaultNotChecked;
 
 // Export '$$default' early to allow circular import from the '.bs.js' file.
diff --git a/jscomp/gentype_tests/typescript-react-example/src/JSXV4.gen.tsx b/jscomp/gentype_tests/typescript-react-example/src/JSXV4.gen.tsx
index fe1b67a982..2e6c911712 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/JSXV4.gen.tsx
+++ b/jscomp/gentype_tests/typescript-react-example/src/JSXV4.gen.tsx
@@ -6,7 +6,7 @@ import {make as makeNotChecked} from './hookExample';
 
 import * as React from 'react';
 
-// In case of type error, check the type of 'make' in 'JSXV4.re' and './hookExample'.
+// In case of type error, check the type of 'make' in 'JSXV4.res' and './hookExample'.
 export const makeTypeChecked: React.ComponentType<{
   readonly actions?: JSX.Element; 
   readonly person: person; 
diff --git a/jscomp/gentype_tests/typescript-react-example/src/MyInput.gen.tsx b/jscomp/gentype_tests/typescript-react-example/src/MyInput.gen.tsx
index 67c7d78233..43af5fc54a 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/MyInput.gen.tsx
+++ b/jscomp/gentype_tests/typescript-react-example/src/MyInput.gen.tsx
@@ -4,7 +4,7 @@
 
 import {default as defaultNotChecked} from './MyInput';
 
-// In case of type error, check the type of 'default' in 'MyInput.re' and './MyInput'.
+// In case of type error, check the type of 'default' in 'MyInput.res' and './MyInput'.
 export const defaultTypeChecked: React.ComponentType<{ readonly onFocus?: (_1:inputFocusEvent) => void }> = defaultNotChecked;
 
 // Export '$$default' early to allow circular import from the '.bs.js' file.
diff --git a/jscomp/ounit_tests/ounit_string_tests.ml b/jscomp/ounit_tests/ounit_string_tests.ml
index b077704950..7502e74232 100644
--- a/jscomp/ounit_tests/ounit_string_tests.ml
+++ b/jscomp/ounit_tests/ounit_string_tests.ml
@@ -72,12 +72,12 @@ let suites =
     (* __LOC__ >:: begin fun _ -> 
       OUnit.assert_bool __LOC__ @@
       List.for_all (fun x -> Ext_string.is_valid_source_name x = Good)
-        ["x.ml"; "x.mli"; "x.re"; "x.rei"; 
+        ["x.ml"; "x.mli"; "x.res"; "x.resi"; 
          "A_x.ml"; "ab.ml"; "a_.ml"; "a__.ml";
          "ax.ml"];
       OUnit.assert_bool __LOC__ @@ not @@
       List.exists (fun x -> Ext_string.is_valid_source_name x = Good)
-        [".re"; ".rei";"..re"; "..rei"; "..ml"; ".mll~"; 
+        [".res"; ".resi";"..res"; "..resi"; "..ml"; ".mll~"; 
          "...ml"; "_.mli"; "_x.ml"; "__.ml"; "__.rei"; 
          ".#hello.ml"; ".#hello.rei"; "a-.ml"; "a-b.ml"; "-a-.ml"
         ; "-.ml"
@@ -486,7 +486,10 @@ let suites =
           (Ext_filename.module_name "a/b/c.d")
           "C";
         string_eq 
-          (Ext_filename.module_name "a/b/xc.re")
+          (Ext_filename.module_name "a/b/xc.res")
+          "Xc";
+        string_eq 
+          (Ext_filename.module_name "a/b/xc.resi")
           "Xc";
         string_eq 
           (Ext_filename.module_name "a/b/xc.ml")
diff --git a/jscomp/test/ext_string_test.js b/jscomp/test/ext_string_test.js
index 014e800457..e6ff377110 100644
--- a/jscomp/test/ext_string_test.js
+++ b/jscomp/test/ext_string_test.js
@@ -493,11 +493,11 @@ function is_valid_source_name(name) {
   var x = check_any_suffix_case_then_chop(name, {
         hd: ".ml",
         tl: {
-          hd: ".re",
+          hd: ".res",
           tl: {
             hd: ".mli",
             tl: {
-              hd: ".rei",
+              hd: ".resi",
               tl: /* [] */0
             }
           }
diff --git a/jscomp/test/ext_string_test.ml b/jscomp/test/ext_string_test.ml
index 7cbb4b58cb..5091d18962 100644
--- a/jscomp/test/ext_string_test.ml
+++ b/jscomp/test/ext_string_test.ml
@@ -363,9 +363,9 @@ type check_result =
 let is_valid_source_name name : check_result =
   match check_any_suffix_case_then_chop name [
       ".ml"; 
-      ".re";
+      ".res";
       ".mli"; 
-      ".rei"
+      ".resi"
     ] with 
   | None -> Suffix_mismatch
   | Some x -> 
diff --git a/lib/4.06.1/rescript.ml b/lib/4.06.1/rescript.ml
index df3a112b63..647af071f0 100644
--- a/lib/4.06.1/rescript.ml
+++ b/lib/4.06.1/rescript.ml
@@ -4387,7 +4387,7 @@ type file_group = {
   (* false means not in dev mode *)
   generators : build_generator list;
       (* output of [generators] should be added to [sources],
-         if it is [.ml,.mli,.re,.rei]
+         if it is [.ml,.mli,.res,.resi]
       *)
 }
 
@@ -4445,7 +4445,7 @@ type file_group = {
   is_dev : bool;
   generators : build_generator list;
       (* output of [generators] should be added to [sources],
-         if it is [.ml,.mli,.re,.rei]
+         if it is [.ml,.mli,.res,.resi]
       *)
 }
 
diff --git a/lib/4.06.1/unstable/all_ounit_tests.ml b/lib/4.06.1/unstable/all_ounit_tests.ml
index 2524808d9f..b10d320122 100644
--- a/lib/4.06.1/unstable/all_ounit_tests.ml
+++ b/lib/4.06.1/unstable/all_ounit_tests.ml
@@ -38647,12 +38647,12 @@ let suites =
     (* __LOC__ >:: begin fun _ -> 
       OUnit.assert_bool __LOC__ @@
       List.for_all (fun x -> Ext_string.is_valid_source_name x = Good)
-        ["x.ml"; "x.mli"; "x.re"; "x.rei"; 
+        ["x.ml"; "x.mli"; "x.res"; "x.resi"; 
          "A_x.ml"; "ab.ml"; "a_.ml"; "a__.ml";
          "ax.ml"];
       OUnit.assert_bool __LOC__ @@ not @@
       List.exists (fun x -> Ext_string.is_valid_source_name x = Good)
-        [".re"; ".rei";"..re"; "..rei"; "..ml"; ".mll~"; 
+        [".res"; ".resi";"..res"; "..resi"; "..ml"; ".mll~"; 
          "...ml"; "_.mli"; "_x.ml"; "__.ml"; "__.rei"; 
          ".#hello.ml"; ".#hello.rei"; "a-.ml"; "a-b.ml"; "-a-.ml"
         ; "-.ml"
@@ -39061,7 +39061,10 @@ let suites =
           (Ext_filename.module_name "a/b/c.d")
           "C";
         string_eq 
-          (Ext_filename.module_name "a/b/xc.re")
+          (Ext_filename.module_name "a/b/xc.res")
+          "Xc";
+        string_eq 
+          (Ext_filename.module_name "a/b/xc.resi")
           "Xc";
         string_eq 
           (Ext_filename.module_name "a/b/xc.ml")
diff --git a/lib/4.06.1/whole_compiler.ml b/lib/4.06.1/whole_compiler.ml
index 63036f7600..6c0b129304 100644
--- a/lib/4.06.1/whole_compiler.ml
+++ b/lib/4.06.1/whole_compiler.ml
@@ -239914,20 +239914,17 @@ let apply ~resolver ~useBsDependencies moduleName =
   moduleName |> Lazy.force resolver.lazyFind ~useBsDependencies
 
 (** Resolve a reference to ModuleName, and produce a path suitable for require.
-   E.g. require "../foo/bar/ModuleName.ext" where ext is ".re" or ".js". *)
+   E.g. require "../foo/bar/ModuleName.ext" where ext is ".res" or ".js". *)
 let resolveModule ~(config : Config.t) ~importExtension ~outputFileRelative
     ~resolver ~useBsDependencies moduleName =
   let outputFileRelativeDir =
-    (* e.g. src if we're generating src/File.re.js *)
+    (* e.g. src if we're generating src/File.bs.js *)
     Filename.dirname outputFileRelative
   in
   let outputFileAbsoluteDir = config.projectRoot +++ outputFileRelativeDir in
-  let moduleNameReFile =
-    (* Check if the module is in the same directory as the file being generated.
-       So if e.g. project_root/src/ModuleName.re exists. *)
-    outputFileAbsoluteDir +++ (ModuleName.toString moduleName ^ ".re")
-  in
   let moduleNameResFile =
+    (* Check if the module is in the same directory as the file being generated.
+       So if e.g. project_root/src/ModuleName.res exists. *)
     outputFileAbsoluteDir +++ (ModuleName.toString moduleName ^ ".res")
   in
   let candidate =
@@ -239935,7 +239932,7 @@ let resolveModule ~(config : Config.t) ~importExtension ~outputFileRelative
     moduleName
     |> ImportPath.fromModule ~dir:Filename.current_dir_name ~importExtension
   in
-  if Sys.file_exists moduleNameReFile || Sys.file_exists moduleNameResFile then
+  if Sys.file_exists moduleNameResFile then
     candidate
   else
     let rec pathToList path =
@@ -239948,7 +239945,7 @@ let resolveModule ~(config : Config.t) ~importExtension ~outputFileRelative
     match moduleName |> apply ~resolver ~useBsDependencies with
     | None -> candidate
     | Some (resolvedModuleDir, case, bsDependencies) ->
-        (* e.g. "dst" in case of dst/ModuleName.re  *)
+        (* e.g. "dst" in case of dst/ModuleName.res *)
         let walkUpOutputDir =
           outputFileRelativeDir |> pathToList
           |> List.map (fun _ -> Filename.parent_dir_name)
@@ -240068,7 +240065,7 @@ let getBsConfigFile ~projectRoot =
   match bsconfig |> Sys.file_exists with true -> Some bsconfig | false -> None
 
 (** Find the relative path from /.../bs/lib
-   e.g. /foo/bar/bs/lib/src/Hello.re --> src/Hello.re *)
+   e.g. /foo/bar/bs/lib/src/Hello.res --> src/Hello.res *)
 let relativePathFromBsLib fileName =
   if Filename.is_relative fileName then fileName
   else
@@ -241887,7 +241884,7 @@ let emitCodeItem ~config ~emitters ~moduleItemsEmitter ~env ~fileName
                ("In case of type error, check the type of '" ^ valueName
               ^ "' in '"
                ^ (fileName |> ModuleName.toString)
-               ^ ".re'" ^ " and '"
+               ^ ".res'" ^ " and '"
                ^ (importPath |> ImportPath.emit)
                ^ "'.")
              ~early:true ~emitters ~name:valueNameTypeChecked ~type_
@@ -243649,9 +243646,9 @@ let processCmtFile cmt =
     let isInterface = Filename.check_suffix cmtFile ".cmti" in
     let resolver =
       ModuleResolver.createLazyResolver ~config
-        ~extensions:[ ".re"; ".res"; EmitType.shimExtension ]
+        ~extensions:[ ".res"; EmitType.shimExtension ]
         ~excludeFile:(fun fname ->
-          fname = "React.re" || fname = "ReasonReact.re")
+          fname = "React.res" || fname = "ReasonReact.res")
     in
     let inputCMT, hasGenTypeAnnotations =
       let inputCMT = readCmt cmtFile in
diff --git a/scripts/littlecase.js b/scripts/littlecase.js
index 3c71fafbf4..ba17568e10 100644
--- a/scripts/littlecase.js
+++ b/scripts/littlecase.js
@@ -7,7 +7,7 @@ function copyReasonReact() {
   let dir = path.join(__dirname, "..", "..", "reason-react", "src");
   let files = fs.readdirSync(dir);
   files.forEach(x => {
-    if (!(x.endsWith(".re") || x.endsWith(".rei"))) {
+    if (!(x.endsWith(".res") || x.endsWith(".resi"))) {
       return;
     }
     let little = x[0].toLowerCase() + x.slice(1);
diff --git a/scripts/ninja.js b/scripts/ninja.js
index 01bb53c00b..7c841506eb 100755
--- a/scripts/ninja.js
+++ b/scripts/ninja.js
@@ -567,9 +567,9 @@ function replaceCmj(x) {
  * @param {string} y
  */
 function sourceToTarget(y) {
-  if (y.endsWith(".ml") || y.endsWith(".re") || y.endsWith(".res")) {
+  if (y.endsWith(".ml") || y.endsWith(".res")) {
     return replaceExt(y, ".cmj");
-  } else if (y.endsWith(".mli") || y.endsWith(".rei") || y.endsWith(".resi")) {
+  } else if (y.endsWith(".mli") || y.endsWith(".resi")) {
     return replaceExt(y, ".cmi");
   }
   return y;
@@ -626,7 +626,6 @@ function ocamlDepForBscAsync(files, dir, depsMap) {
  */
 function depModulesForBscAsync(files, dir, depsMap) {
   let ocamlFiles = files.filter(x => x.endsWith(".ml") || x.endsWith(".mli"));
-  let reFiles = files.filter(x => x.endsWith(".re") || x.endsWith(".rei"));
   let resFiles = files.filter(x => x.endsWith(".res") || x.endsWith(".resi"));
   /**
    *
@@ -666,7 +665,7 @@ function depModulesForBscAsync(files, dir, depsMap) {
       cp.exec(
         `${bsc_exe}  -modules -bs-syntax-only ${resFiles.join(
           " "
-        )} ${reFiles.join(" ")} ${ocamlFiles.join(" ")}`,
+        )} ${ocamlFiles.join(" ")}`,
         config,
         cb(resolve, reject)
       );
@@ -675,7 +674,7 @@ function depModulesForBscAsync(files, dir, depsMap) {
 }
 
 /**
- * @typedef {('HAS_ML' | 'HAS_MLI' | 'HAS_BOTH' | 'HAS_RE' | 'HAS_RES' | 'HAS_REI' | 'HAS_RESI' | 'HAS_BOTH_RE' | 'HAS_BOTH_RES')} FileInfo
+ * @typedef {('HAS_ML' | 'HAS_MLI' | 'HAS_BOTH' | 'HAS_RES' | 'HAS_RESI' | 'HAS_BOTH_RES')} FileInfo
  * @param {string[]} sourceFiles
  * @returns {Map<string, FileInfo>}
  * We make a set to ensure that `sourceFiles` are not duplicated
@@ -693,12 +692,8 @@ function collectTarget(sourceFiles) {
         allTargets.set(name, "HAS_ML");
       } else if (ext === ".mli") {
         allTargets.set(name, "HAS_MLI");
-      } else if (ext === ".re") {
-        allTargets.set(name, "HAS_RE");
       } else if (ext === ".res") {
         allTargets.set(name, "HAS_RES");
-      } else if (ext === ".rei") {
-        allTargets.set(name, "HAS_REI");
       } else if (ext === ".resi") {
         allTargets.set(name, "HAS_RESI");
       }
@@ -709,11 +704,6 @@ function collectTarget(sourceFiles) {
             allTargets.set(name, "HAS_BOTH");
           }
           break;
-        case "HAS_RE":
-          if (ext === ".rei") {
-            allTargets.set(name, "HAS_BOTH_RE");
-          }
-          break;
         case "HAS_RES":
           if (ext === ".resi") {
             allTargets.set(name, "HAS_BOTH_RES");
@@ -724,17 +714,11 @@ function collectTarget(sourceFiles) {
             allTargets.set(name, "HAS_BOTH");
           }
           break;
-        case "HAS_REI":
-          if (ext === ".re") {
-            allTargets.set(name, "HAS_BOTH_RE");
-          }
-          break;
         case "HAS_RESI":
           if (ext === ".res") {
             allTargets.set(name, "HAS_BOTH_RES");
           }
           break;
-        case "HAS_BOTH_RE":
         case "HAS_BOTH":
         case "HAS_BOTH_RES":
           break;
@@ -755,17 +739,14 @@ function scanFileTargets(allTargets, collIn) {
   var coll = collIn.concat();
   allTargets.forEach((ext, mod) => {
     switch (ext) {
-      case "HAS_MLI":
-      case "HAS_REI":
       case "HAS_RESI":
+      case "HAS_MLI":
         coll.push(`${mod}.cmi`);
         break;
       case "HAS_BOTH_RES":
-      case "HAS_BOTH_RE":
       case "HAS_BOTH":
         coll.push(`${mod}.cmi`, `${mod}.cmj`);
         break;
-      case "HAS_RE":
       case "HAS_RES":
       case "HAS_ML":
         coll.push(`${mod}.cmi`, `${mod}.cmj`);
@@ -793,9 +774,7 @@ function generateNinja(depsMap, allTargets, cwd, extraDeps = []) {
     let output_cmi = mod + ".cmi";
     let input_ml = mod + ".ml";
     let input_mli = mod + ".mli";
-    let input_re = mod + ".re";
     let input_res = mod + ".res";
-    let input_rei = mod + ".rei";
     let input_resi = mod + ".resi";
     /**
      * @type {Override[]}
@@ -821,26 +800,16 @@ function generateNinja(depsMap, allTargets, cwd, extraDeps = []) {
         mk([ouptput_cmj], [input_ml], "cc_cmi");
         mk([output_cmi], [input_mli]);
         break;
-      case "HAS_BOTH_RE":
-        mk([ouptput_cmj], [input_re], "cc_cmi");
-        mk([output_cmi], [input_rei], "cc");
-        break;
       case "HAS_BOTH_RES":
         mk([ouptput_cmj], [input_res], "cc_cmi");
         mk([output_cmi], [input_resi], "cc");
         break;
-      case "HAS_RE":
-        mk([output_cmi, ouptput_cmj], [input_re], "cc");
-        break;
       case "HAS_RES":
         mk([output_cmi, ouptput_cmj], [input_res], "cc");
         break;
       case "HAS_ML":
         mk([output_cmi, ouptput_cmj], [input_ml]);
         break;
-      case "HAS_REI":
-        mk([output_cmi], [input_rei], "cc");
-        break;
       case "HAS_RESI":
         mk([output_cmi], [input_resi], "cc");
         break;
@@ -1215,8 +1184,6 @@ ${mllList(ninjaCwd, [
   var testDirFiles = fs.readdirSync(testDir, "ascii");
   var sources = testDirFiles.filter(x => {
     return (
-      x.endsWith(".re") ||
-      x.endsWith(".rei") ||
       x.endsWith(".resi") ||
       x.endsWith(".res") ||
       ((x.endsWith(".ml") || x.endsWith(".mli")) && !x.endsWith("bspack.ml"))
diff --git a/scripts/rescript_convert.js b/scripts/rescript_convert.js
index 02db4b94fb..e7f37419bf 100644
--- a/scripts/rescript_convert.js
+++ b/scripts/rescript_convert.js
@@ -4,7 +4,7 @@ var format_usage = `Usage: rescript convert <options> [files]
 
 \`rescript convert\` converts the current directory
 
-**This command removes old Reason/OCaml files and creates new ReScript 
+**This command removes old OCaml files and creates new ReScript 
 files. Make sure your work is saved first!**
 `;
 
@@ -33,7 +33,7 @@ var specs = [
  * @param {string} file
  */
 function shouldConvert(file) {
-  return [".ml", ".mli", ".re", ".rei"].some(x => file.endsWith(x));
+  return [".ml", ".mli"].some(x => file.endsWith(x));
 }
 
 /**
diff --git a/scripts/tasks.js b/scripts/tasks.js
index e64699b0e2..53eac5d4aa 100644
--- a/scripts/tasks.js
+++ b/scripts/tasks.js
@@ -88,8 +88,6 @@ function onSourceChange(eventType, filename) {
     filename.endsWith(".mll") ||
     filename.endsWith(".mly") ||
     filename.endsWith(".json") ||
-    filename.endsWith(".re") ||
-    filename.endsWith(".rei") ||
     filename.endsWith(".res") ||
     filename.endsWith(".resi")
   ) {