diff --git a/README.md b/README.md
index ee733b6..fc5de2e 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ While there are tools like [tsc](https://www.typescriptlang.org/docs/handbook/co
 ## 🚀 Usage
 
 ```bash
-npx mkdist [rootDir] [--src=src] [--dist=dist] [--pattern=glob [--pattern=more-glob]] [--format=cjs|esm] [-d|--declaration] [--ext=mjs|js|ts]
+npx mkdist [rootDir] [--src=src] [--dist=dist] [--pattern=glob [--pattern=more-glob]] [--format=cjs|esm] [-d|--declaration] [--ext=mjs|js|ts] [--declarationExt=infer|d.ts|d.mts|d.cts]
 ```
 
 ## License
diff --git a/src/cli.ts b/src/cli.ts
index 4acc90c..cf0e764 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -46,6 +46,11 @@ const main = defineCommand({
       default: false,
       alias: ["d"],
     },
+    declarationExt: {
+      type: "string",
+      description: "Extensions for type declaration files",
+      valueHint: "infer|d.ts|d.mts|d.cts",
+    },
     ext: {
       type: "string",
       description: "File extension",
@@ -90,6 +95,7 @@ const main = defineCommand({
       pattern: args.pattern,
       ext: args.ext,
       declaration: args.declaration,
+      declarationExt: args.declarationExt,
       loaders: args.loaders?.split(","),
       esbuild: {
         jsx: args.jsx,
diff --git a/src/loader.ts b/src/loader.ts
index 29b0545..9073acf 100644
--- a/src/loader.ts
+++ b/src/loader.ts
@@ -21,6 +21,7 @@ export interface OutputFile {
    */
   path: string;
   srcPath?: string;
+  srcExtension?: string;
   extension?: string;
   contents?: string;
   declaration?: boolean;
@@ -38,6 +39,7 @@ export interface LoaderOptions {
   ext?: "js" | "mjs" | "cjs" | "ts" | "mts" | "cts";
   format?: "cjs" | "esm";
   declaration?: boolean;
+  declarationExt?: "infer" | "d.ts" | "d.mts" | "d.cts";
   esbuild?: CommonOptions;
   postcss?:
     | false
diff --git a/src/loaders/js.ts b/src/loaders/js.ts
index e7e79fe..7ab2764 100644
--- a/src/loaders/js.ts
+++ b/src/loaders/js.ts
@@ -11,25 +11,56 @@ const KNOWN_EXT_RE = /\.(c|m)?[jt]sx?$/;
 const TS_EXTS = new Set([".ts", ".mts", ".cts"]);
 
 export const jsLoader: Loader = async (input, { options }) => {
-  if (!KNOWN_EXT_RE.test(input.path) || DECLARATION_RE.test(input.path)) {
+  if (!KNOWN_EXT_RE.test(input.path)) {
     return;
   }
 
   const output: LoaderResult = [];
 
   let contents = await input.getContents();
+  const [explicitDtsExtension] = input.srcPath?.match(DECLARATION_RE) ?? [];
+  const isManualDts = !!explicitDtsExtension;
 
   // declaration
-  if (options.declaration && !input.srcPath?.match(DECLARATION_RE)) {
+  if (options.declaration || isManualDts) {
     const cm = input.srcPath?.match(CM_LETTER_RE)?.[0] || "";
-    const extension = `.d.${cm}ts`;
+
+    const extension = (() => {
+      if (options.declarationExt === "infer") {
+        return (
+          {
+            js: ".d.ts",
+            mjs: ".d.mts",
+            cjs: ".d.cts",
+            ts: ".d.ts",
+            mts: ".d.mts",
+            cts: ".d.cts",
+          }[options.ext?.replace(/^\./, "")] ??
+          {
+            esm: ".d.mts",
+            cjs: ".d.ts", // TODO: Change it to ".d.cts" in next major version
+          }[options.format ?? "esm"]
+        );
+      } else if (options.declarationExt) {
+        return `.${options.declarationExt}`;
+      } else {
+        return `.d.${cm}ts`;
+      }
+    })();
+
     output.push({
       contents,
       srcPath: input.srcPath,
+      srcExtension: isManualDts ? explicitDtsExtension : undefined,
       path: input.path,
       extension,
+      raw: isManualDts,
       declaration: true,
     });
+
+    if (isManualDts) {
+      return output;
+    }
   }
 
   // typescript => js
diff --git a/src/loaders/vue.ts b/src/loaders/vue.ts
index 4e5aaf1..030ca89 100644
--- a/src/loaders/vue.ts
+++ b/src/loaders/vue.ts
@@ -124,5 +124,5 @@ const scriptLoader = vueBlockLoader({
   outputLang: "js",
   type: "script",
   exclude: [/\bsetup\b/],
-  validExtensions: [".js", ".mjs"],
+  validExtensions: [".js", ".mjs", ".ts", ".mts"],
 });
diff --git a/src/make.ts b/src/make.ts
index c21f5cc..a38dbc1 100644
--- a/src/make.ts
+++ b/src/make.ts
@@ -92,7 +92,8 @@ export async function mkdist(
   // Normalize output extensions
   for (const output of outputs.filter((o) => o.extension)) {
     const renamed =
-      basename(output.path, extname(output.path)) + output.extension;
+      basename(output.path, output.srcExtension ?? extname(output.path)) +
+      output.extension;
     output.path = join(dirname(output.path), renamed);
     // Avoid overriding files with original extension
     if (outputs.some((o) => o !== output && o.path === output.path)) {
diff --git a/test/index.test.ts b/test/index.test.ts
index eec3812..8fa37b4 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -192,6 +192,211 @@ describe("mkdist", () => {
     `);
   }, 50_000);
 
+  describe("mkdist (declarationExt: infer)", () => {
+    it.each([
+      {
+        format: "cjs",
+        ext: undefined,
+        implicitFiles: [
+          "dist/foo.js",
+          "dist/foo.d.ts",
+          "dist/bar.js",
+          "dist/bar.d.ts",
+          "dist/index.js",
+          "dist/index.d.ts",
+          "dist/star/index.js",
+          "dist/star/index.d.ts",
+          "dist/star/other.js",
+          "dist/star/other.d.ts",
+          "dist/types.d.ts",
+          "dist/bar/index.js",
+          "dist/bar/index.d.ts",
+          "dist/bar/esm.js",
+          "dist/bar/esm.d.ts",
+          "dist/ts/test1.js",
+          "dist/ts/test2.js",
+          "dist/ts/test1.d.ts",
+          "dist/ts/test2.d.ts",
+          "dist/components/js.vue.d.ts",
+          "dist/components/ts.vue.d.ts",
+          "dist/components/jsx.js",
+          "dist/components/tsx.js",
+          "dist/components/jsx.d.ts",
+          "dist/components/tsx.d.ts",
+          "dist/dir-export.js",
+          "dist/dir-export.d.ts",
+          "dist/components/index.d.ts",
+          "dist/components/index.js",
+          "dist/components/script-multi-block.vue",
+        ],
+      },
+      // not setting the format explicitly should work like esm
+      ...(["esm", undefined] as const).map((format) => ({
+        format,
+        ext: undefined,
+        implicitFiles: [
+          "dist/foo.mjs",
+          "dist/foo.d.mts",
+          "dist/bar.mjs",
+          "dist/bar.d.mts",
+          "dist/index.mjs",
+          "dist/index.d.mts",
+          "dist/star/index.mjs",
+          "dist/star/index.d.mts",
+          "dist/star/other.mjs",
+          "dist/star/other.d.mts",
+          "dist/types.d.mts",
+          "dist/bar/index.mjs",
+          "dist/bar/index.d.mts",
+          "dist/bar/esm.mjs",
+          "dist/bar/esm.d.mts",
+          "dist/ts/test1.mjs",
+          "dist/ts/test2.mjs",
+          "dist/ts/test1.d.mts",
+          "dist/ts/test2.d.mts",
+          "dist/components/js.vue.d.mts",
+          "dist/components/ts.vue.d.mts",
+          "dist/components/jsx.mjs",
+          "dist/components/tsx.mjs",
+          "dist/components/jsx.d.mts",
+          "dist/components/tsx.d.mts",
+          "dist/dir-export.mjs",
+          "dist/dir-export.d.mts",
+          "dist/components/index.d.mts",
+          "dist/components/index.mjs",
+          "dist/components/script-multi-block.vue",
+        ],
+      })),
+      ...(["cjs", "esm", undefined] as const).flatMap((format) =>
+        (["js", "mjs", "cjs", "ts", "mts", "cts"] as const).map((ext) => {
+          const [srcExt, dtsExt, emitsVue = false] = {
+            js: ["js", "d.ts", true],
+            mjs: ["mjs", "d.mts", true],
+            cjs: ["cjs", "d.cts"],
+            ts: ["ts", "d.ts", true],
+            mts: ["mts", "d.mts", true],
+            cts: ["cts", "d.cts"],
+          }[ext];
+
+          return {
+            format,
+            ext,
+            implicitFiles: [
+              `dist/foo.${srcExt}`,
+              `dist/foo.${dtsExt}`,
+              `dist/bar.${srcExt}`,
+              `dist/bar.${dtsExt}`,
+              `dist/index.${srcExt}`,
+              `dist/index.${dtsExt}`,
+              `dist/star/index.${srcExt}`,
+              `dist/star/index.${dtsExt}`,
+              `dist/star/other.${srcExt}`,
+              `dist/star/other.${dtsExt}`,
+              `dist/types.${dtsExt}`,
+              `dist/bar/index.${srcExt}`,
+              `dist/bar/index.${dtsExt}`,
+              `dist/bar/esm.${srcExt}`,
+              `dist/bar/esm.${dtsExt}`,
+              `dist/ts/test1.${srcExt}`,
+              `dist/ts/test2.${srcExt}`,
+              `dist/ts/test1.${dtsExt}`,
+              `dist/ts/test2.${dtsExt}`,
+              `dist/components/jsx.${srcExt}`,
+              `dist/components/tsx.${srcExt}`,
+              `dist/components/jsx.${dtsExt}`,
+              `dist/components/tsx.${dtsExt}`,
+              `dist/dir-export.${srcExt}`,
+              `dist/dir-export.${dtsExt}`,
+              `dist/components/index.${srcExt}`,
+              `dist/components/index.${dtsExt}`,
+              `dist/components/script-multi-block.vue`,
+              ...(emitsVue
+                ? [
+                    `dist/components/js.vue.${dtsExt}`,
+                    `dist/components/ts.vue.${dtsExt}`,
+                  ]
+                : []),
+            ],
+          };
+        }),
+      ),
+    ] as const)(
+      "format: $format, ext: $ext",
+      async ({ format, ext, implicitFiles }) => {
+        const rootDir = resolve(__dirname, "fixture");
+        const { writtenFiles } = await mkdist({
+          rootDir,
+          format,
+          ext,
+          declaration: true,
+          declarationExt: "infer",
+        });
+        expect(writtenFiles.sort()).toEqual(
+          [
+            "dist/README.md",
+            "dist/demo.css",
+            "dist/components/blank.vue",
+            "dist/components/js.vue",
+            "dist/components/script-setup-ts.vue",
+            "dist/components/ts.vue",
+            "dist/nested.css",
+            ...implicitFiles,
+          ]
+            .map((f) => resolve(rootDir, f))
+            .sort(),
+        );
+      },
+    );
+  }, 50_000);
+
+  it.each(["d.ts", "d.mts", "d.cts"] as const)(
+    "mkdist (declarationExt: %s)",
+    async (declarationExt) => {
+      const rootDir = resolve(__dirname, "fixture");
+      const { writtenFiles } = await mkdist({
+        rootDir,
+        declaration: true,
+        declarationExt,
+      });
+      expect(writtenFiles.sort()).toEqual(
+        [
+          "dist/README.md",
+          "dist/demo.css",
+          "dist/foo.mjs",
+          `dist/foo.${declarationExt}`,
+          "dist/index.mjs",
+          `dist/index.${declarationExt}`,
+          "dist/star/index.mjs",
+          `dist/star/index.${declarationExt}`,
+          "dist/star/other.mjs",
+          `dist/star/other.${declarationExt}`,
+          `dist/types.${declarationExt}`,
+          "dist/components/blank.vue",
+          "dist/components/js.vue",
+          `dist/components/js.vue.${declarationExt}`,
+          "dist/components/script-setup-ts.vue",
+          "dist/components/ts.vue",
+          `dist/components/ts.vue.${declarationExt}`,
+          "dist/components/jsx.mjs",
+          "dist/components/tsx.mjs",
+          `dist/components/jsx.${declarationExt}`,
+          `dist/components/tsx.${declarationExt}`,
+          "dist/bar/index.mjs",
+          `dist/bar/index.${declarationExt}`,
+          "dist/bar/esm.mjs",
+          `dist/bar/esm.${declarationExt}`,
+          "dist/ts/test1.mjs",
+          "dist/ts/test2.mjs",
+          `dist/ts/test1.${declarationExt}`,
+          `dist/ts/test2.${declarationExt}`,
+          "dist/nested.css",
+        ]
+          .map((f) => resolve(rootDir, f))
+          .sort(),
+      );
+    },
+  );
+
   describe("mkdist (sass compilation)", () => {
     const rootDir = resolve(__dirname, "fixture");
     let writtenFiles: string[];