diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index bd9b42caae953..eb1e37416b880 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1396,7 +1396,7 @@ export function getImpliedNodeFormatForFileWorker(
     const shouldLookupFromPackageJson = ModuleResolutionKind.Node16 <= moduleResolution && moduleResolution <= ModuleResolutionKind.NodeNext
         || pathContainsNodeModules(fileName);
     return fileExtensionIsOneOf(fileName, [Extension.Dmts, Extension.Mts, Extension.Mjs]) ? ModuleKind.ESNext :
-        fileExtensionIsOneOf(fileName, [Extension.Dcts, Extension.Cts, Extension.Cjs]) ? ModuleKind.CommonJS :
+        fileExtensionIsOneOf(fileName, [Extension.Dcts, Extension.Cts, Extension.Cjs]) || (isDeclarationFileName(fileName) && !fileExtensionIs(fileName, Extension.Dts)) ? ModuleKind.CommonJS :
         shouldLookupFromPackageJson && fileExtensionIsOneOf(fileName, [Extension.Dts, Extension.Ts, Extension.Tsx, Extension.Js, Extension.Jsx]) ? lookupFromPackageJson() :
         undefined; // other extensions, like `json` or `tsbuildinfo`, are set as `undefined` here but they should never be fed through the transformer pipeline
 
diff --git a/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.errors.txt b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.errors.txt
new file mode 100644
index 0000000000000..73230c800836e
--- /dev/null
+++ b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.errors.txt
@@ -0,0 +1,66 @@
+cjs/index.mts(2,6): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+cjs/index.mts(4,7): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+cjs/secondary.cts(2,6): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+cjs/secondary.cts(4,7): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+esm/index.mts(2,6): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+esm/index.mts(4,7): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+esm/secondary.cts(2,6): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+esm/secondary.cts(4,7): error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+
+
+==== cjs/package.json (0 errors) ====
+    { "type": "commonjs" }
+==== cjs/foo.json (0 errors) ====
+    ["foo", "bar", "baz"]
+==== cjs/foo.d.json.ts (0 errors) ====
+    declare const data: ["foo", "bar", "baz"];
+    export = data;
+==== cjs/index.mts (2 errors) ====
+    import data from "./foo.json" with { type: "json" };
+    data.default; // foo.d.json.ts is cjs format - error (`default` is whole file, file has no `default` member)
+         ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+    import data2 = require("./foo.json");
+    data2.default; // `data2` is the whole json object, no `default`
+          ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+==== cjs/secondary.cts (2 errors) ====
+    import data from "./foo.json";
+    data.default; // error (cjs format `.d.json.ts`, export= object is require result)
+         ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+    import data2 = require("./foo.json");
+    data2.default; // `data2` is the whole json object, no `default`
+          ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+==== esm/package.json (0 errors) ====
+    { "type": "module" }
+==== esm/foo.json (0 errors) ====
+    ["foo", "bar", "baz"]
+==== esm/foo.d.json.ts (0 errors) ====
+    declare const data: ["foo", "bar", "baz"];
+    export = data;
+==== esm/index.mts (2 errors) ====
+    import data from "./foo.json" with { type: "json" };
+    data.default; // foo.d.json.ts is cjs format despite package - error! (default import is already the whole json object)
+         ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+    import data2 = require("./foo.json");
+    data2.default; // `data2` is the whole json object, no `default`
+          ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+==== esm/secondary.cts (2 errors) ====
+    import data from "./foo.json";
+    data.default; // `export=` object is the whole `require` result, hoisted to `default` by interop helper, no 2nd default
+         ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+    import data2 = require("./foo.json");
+    data2.default; // `data2` is the whole json object, no `default`
+          ~~~~~~~
+!!! error TS2339: Property 'default' does not exist on type '["foo", "bar", "baz"]'.
+==== root.mts (0 errors) ====
+    import "./cjs/index.mjs";
+    import "./cjs/secondary.mjs";
+    import "./mjs/index.mjs";
+    import "./mjs/secondary.mjs";
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.js b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.js
new file mode 100644
index 0000000000000..ea16f843da3d7
--- /dev/null
+++ b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.js
@@ -0,0 +1,97 @@
+//// [tests/cases/compiler/resolveJsonModuleAllowArbitraryExtensionsNodeNext.ts] ////
+
+//// [package.json]
+{ "type": "commonjs" }
+//// [foo.json]
+["foo", "bar", "baz"]
+//// [foo.d.json.ts]
+declare const data: ["foo", "bar", "baz"];
+export = data;
+//// [index.mts]
+import data from "./foo.json" with { type: "json" };
+data.default; // foo.d.json.ts is cjs format - error (`default` is whole file, file has no `default` member)
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [secondary.cts]
+import data from "./foo.json";
+data.default; // error (cjs format `.d.json.ts`, export= object is require result)
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [package.json]
+{ "type": "module" }
+//// [foo.json]
+["foo", "bar", "baz"]
+//// [foo.d.json.ts]
+declare const data: ["foo", "bar", "baz"];
+export = data;
+//// [index.mts]
+import data from "./foo.json" with { type: "json" };
+data.default; // foo.d.json.ts is cjs format despite package - error! (default import is already the whole json object)
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [secondary.cts]
+import data from "./foo.json";
+data.default; // `export=` object is the whole `require` result, hoisted to `default` by interop helper, no 2nd default
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [root.mts]
+import "./cjs/index.mjs";
+import "./cjs/secondary.mjs";
+import "./mjs/index.mjs";
+import "./mjs/secondary.mjs";
+
+
+//// [index.mjs]
+import { createRequire as _createRequire } from "module";
+const __require = _createRequire(import.meta.url);
+import data from "./foo.json" with { type: "json" };
+data.default; // foo.d.json.ts is cjs format - error (`default` is whole file, file has no `default` member)
+const data2 = __require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [secondary.cjs]
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const foo_json_1 = __importDefault(require("./foo.json"));
+foo_json_1.default.default; // error (cjs format `.d.json.ts`, export= object is require result)
+const data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [index.mjs]
+import { createRequire as _createRequire } from "module";
+const __require = _createRequire(import.meta.url);
+import data from "./foo.json" with { type: "json" };
+data.default; // foo.d.json.ts is cjs format despite package - error! (default import is already the whole json object)
+const data2 = __require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [secondary.cjs]
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const foo_json_1 = __importDefault(require("./foo.json"));
+foo_json_1.default.default; // `export=` object is the whole `require` result, hoisted to `default` by interop helper, no 2nd default
+const data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+//// [root.mjs]
+import "./cjs/index.mjs";
+import "./cjs/secondary.mjs";
+import "./mjs/index.mjs";
+import "./mjs/secondary.mjs";
+
+
+//// [index.d.mts]
+export {};
+//// [secondary.d.cts]
+export {};
+//// [index.d.mts]
+export {};
+//// [secondary.d.cts]
+export {};
+//// [root.d.mts]
+import "./cjs/index.mjs";
+import "./cjs/secondary.mjs";
+import "./mjs/index.mjs";
+import "./mjs/secondary.mjs";
diff --git a/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.symbols b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.symbols
new file mode 100644
index 0000000000000..839f98395110f
--- /dev/null
+++ b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.symbols
@@ -0,0 +1,75 @@
+//// [tests/cases/compiler/resolveJsonModuleAllowArbitraryExtensionsNodeNext.ts] ////
+
+=== cjs/foo.d.json.ts ===
+declare const data: ["foo", "bar", "baz"];
+>data : Symbol(data, Decl(foo.d.json.ts, 0, 13))
+
+export = data;
+>data : Symbol(data, Decl(foo.d.json.ts, 0, 13))
+
+=== cjs/index.mts ===
+import data from "./foo.json" with { type: "json" };
+>data : Symbol(data, Decl(index.mts, 0, 6))
+
+data.default; // foo.d.json.ts is cjs format - error (`default` is whole file, file has no `default` member)
+>data : Symbol(data, Decl(index.mts, 0, 6))
+
+import data2 = require("./foo.json");
+>data2 : Symbol(data2, Decl(index.mts, 1, 13))
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2 : Symbol(data2, Decl(index.mts, 1, 13))
+
+=== cjs/secondary.cts ===
+import data from "./foo.json";
+>data : Symbol(data, Decl(secondary.cts, 0, 6))
+
+data.default; // error (cjs format `.d.json.ts`, export= object is require result)
+>data : Symbol(data, Decl(secondary.cts, 0, 6))
+
+import data2 = require("./foo.json");
+>data2 : Symbol(data2, Decl(secondary.cts, 1, 13))
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2 : Symbol(data2, Decl(secondary.cts, 1, 13))
+
+=== esm/foo.d.json.ts ===
+declare const data: ["foo", "bar", "baz"];
+>data : Symbol(data, Decl(foo.d.json.ts, 0, 13))
+
+export = data;
+>data : Symbol(data, Decl(foo.d.json.ts, 0, 13))
+
+=== esm/index.mts ===
+import data from "./foo.json" with { type: "json" };
+>data : Symbol(data, Decl(index.mts, 0, 6))
+
+data.default; // foo.d.json.ts is cjs format despite package - error! (default import is already the whole json object)
+>data : Symbol(data, Decl(index.mts, 0, 6))
+
+import data2 = require("./foo.json");
+>data2 : Symbol(data2, Decl(index.mts, 1, 13))
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2 : Symbol(data2, Decl(index.mts, 1, 13))
+
+=== esm/secondary.cts ===
+import data from "./foo.json";
+>data : Symbol(data, Decl(secondary.cts, 0, 6))
+
+data.default; // `export=` object is the whole `require` result, hoisted to `default` by interop helper, no 2nd default
+>data : Symbol(data, Decl(secondary.cts, 0, 6))
+
+import data2 = require("./foo.json");
+>data2 : Symbol(data2, Decl(secondary.cts, 1, 13))
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2 : Symbol(data2, Decl(secondary.cts, 1, 13))
+
+=== root.mts ===
+
+import "./cjs/index.mjs";
+import "./cjs/secondary.mjs";
+import "./mjs/index.mjs";
+import "./mjs/secondary.mjs";
+
diff --git a/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.types b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.types
new file mode 100644
index 0000000000000..5c72a10b2aec9
--- /dev/null
+++ b/tests/baselines/reference/resolveJsonModuleAllowArbitraryExtensionsNodeNext.types
@@ -0,0 +1,131 @@
+//// [tests/cases/compiler/resolveJsonModuleAllowArbitraryExtensionsNodeNext.ts] ////
+
+=== cjs/foo.d.json.ts ===
+declare const data: ["foo", "bar", "baz"];
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+
+export = data;
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+
+=== cjs/index.mts ===
+import data from "./foo.json" with { type: "json" };
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+>type : any
+>     : ^^^
+
+data.default; // foo.d.json.ts is cjs format - error (`default` is whole file, file has no `default` member)
+>data.default : any
+>             : ^^^
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+import data2 = require("./foo.json");
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2.default : any
+>              : ^^^
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+=== cjs/secondary.cts ===
+import data from "./foo.json";
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+
+data.default; // error (cjs format `.d.json.ts`, export= object is require result)
+>data.default : any
+>             : ^^^
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+import data2 = require("./foo.json");
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2.default : any
+>              : ^^^
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+=== esm/foo.d.json.ts ===
+declare const data: ["foo", "bar", "baz"];
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+
+export = data;
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+
+=== esm/index.mts ===
+import data from "./foo.json" with { type: "json" };
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+>type : any
+>     : ^^^
+
+data.default; // foo.d.json.ts is cjs format despite package - error! (default import is already the whole json object)
+>data.default : any
+>             : ^^^
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+import data2 = require("./foo.json");
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2.default : any
+>              : ^^^
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+=== esm/secondary.cts ===
+import data from "./foo.json";
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+
+data.default; // `export=` object is the whole `require` result, hoisted to `default` by interop helper, no 2nd default
+>data.default : any
+>             : ^^^
+>data : ["foo", "bar", "baz"]
+>     : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+import data2 = require("./foo.json");
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+
+data2.default; // `data2` is the whole json object, no `default`
+>data2.default : any
+>              : ^^^
+>data2 : ["foo", "bar", "baz"]
+>      : ^^^^^^^^^^^^^^^^^^^^^
+>default : any
+>        : ^^^
+
+=== root.mts ===
+
+import "./cjs/index.mjs";
+import "./cjs/secondary.mjs";
+import "./mjs/index.mjs";
+import "./mjs/secondary.mjs";
+
diff --git a/tests/baselines/reference/tscWatch/resolveJsonModule/incremental-always-prefers-declaration-file-over-document.js b/tests/baselines/reference/tscWatch/resolveJsonModule/incremental-always-prefers-declaration-file-over-document.js
index cf7e08090f750..86aaaff56386c 100644
--- a/tests/baselines/reference/tscWatch/resolveJsonModule/incremental-always-prefers-declaration-file-over-document.js
+++ b/tests/baselines/reference/tscWatch/resolveJsonModule/incremental-always-prefers-declaration-file-over-document.js
@@ -52,7 +52,7 @@ var x = data_json_1.default;
 
 
 //// [/src/project/tsconfig.tsbuildinfo]
-{"fileNames":["../../a/lib/lib.d.ts","./data.d.json.ts","./main.ts"],"fileIdsList":[[2]],"fileInfos":[{"version":"-7698705165-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }","affectsGlobalScope":true},"2718060498-declare var val: string; export default val;","6961905452-import data from \"./data.json\"; let x: string = data;"],"root":[2,3],"referencedMap":[[3,1]],"semanticDiagnosticsPerFile":[[3,[{"start":17,"length":13,"messageText":"Module './data.json' was resolved to '/src/project/data.d.json.ts', but '--allowArbitraryExtensions' is not set.","category":1,"code":6263}]]],"version":"FakeTSVersion"}
+{"fileNames":["../../a/lib/lib.d.ts","./data.d.json.ts","./main.ts"],"fileIdsList":[[2]],"fileInfos":[{"version":"-7698705165-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }","affectsGlobalScope":true},{"version":"2718060498-declare var val: string; export default val;","impliedFormat":1},"6961905452-import data from \"./data.json\"; let x: string = data;"],"root":[2,3],"referencedMap":[[3,1]],"semanticDiagnosticsPerFile":[[3,[{"start":17,"length":13,"messageText":"Module './data.json' was resolved to '/src/project/data.d.json.ts', but '--allowArbitraryExtensions' is not set.","category":1,"code":6263}]]],"version":"FakeTSVersion"}
 
 //// [/src/project/tsconfig.tsbuildinfo.readable.baseline.txt]
 {
@@ -77,8 +77,13 @@ var x = data_json_1.default;
       "affectsGlobalScope": true
     },
     "./data.d.json.ts": {
+      "original": {
+        "version": "2718060498-declare var val: string; export default val;",
+        "impliedFormat": 1
+      },
       "version": "2718060498-declare var val: string; export default val;",
-      "signature": "2718060498-declare var val: string; export default val;"
+      "signature": "2718060498-declare var val: string; export default val;",
+      "impliedFormat": "commonjs"
     },
     "./main.ts": {
       "version": "6961905452-import data from \"./data.json\"; let x: string = data;",
@@ -115,7 +120,7 @@ var x = data_json_1.default;
     ]
   ],
   "version": "FakeTSVersion",
-  "size": 908
+  "size": 938
 }
 
 
diff --git a/tests/cases/compiler/resolveJsonModuleAllowArbitraryExtensionsNodeNext.ts b/tests/cases/compiler/resolveJsonModuleAllowArbitraryExtensionsNodeNext.ts
new file mode 100644
index 0000000000000..73a80157ef9e3
--- /dev/null
+++ b/tests/cases/compiler/resolveJsonModuleAllowArbitraryExtensionsNodeNext.ts
@@ -0,0 +1,44 @@
+// @declaration: true
+// @module: nodenext
+// @allowArbitraryExtensions: true
+// @resolveJsonModule: true
+// @listFiles: true
+// @filename: cjs/package.json
+{ "type": "commonjs" }
+// @filename: cjs/foo.json
+["foo", "bar", "baz"]
+// @filename: cjs/foo.d.json.ts
+declare const data: ["foo", "bar", "baz"];
+export = data;
+// @filename: cjs/index.mts
+import data from "./foo.json" with { type: "json" };
+data.default; // foo.d.json.ts is cjs format - error (`default` is whole file, file has no `default` member)
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+// @filename: cjs/secondary.cts
+import data from "./foo.json";
+data.default; // error (cjs format `.d.json.ts`, export= object is require result)
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+// @filename: esm/package.json
+{ "type": "module" }
+// @filename: esm/foo.json
+["foo", "bar", "baz"]
+// @filename: esm/foo.d.json.ts
+declare const data: ["foo", "bar", "baz"];
+export = data;
+// @filename: esm/index.mts
+import data from "./foo.json" with { type: "json" };
+data.default; // foo.d.json.ts is cjs format despite package - error! (default import is already the whole json object)
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+// @filename: esm/secondary.cts
+import data from "./foo.json";
+data.default; // `export=` object is the whole `require` result, hoisted to `default` by interop helper, no 2nd default
+import data2 = require("./foo.json");
+data2.default; // `data2` is the whole json object, no `default`
+// @filename: root.mts
+import "./cjs/index.mjs";
+import "./cjs/secondary.mjs";
+import "./mjs/index.mjs";
+import "./mjs/secondary.mjs";