diff --git a/cli/tests/integration/npm_tests.rs b/cli/tests/integration/npm_tests.rs
index 25a39b68d2..ddbc79cec1 100644
--- a/cli/tests/integration/npm_tests.rs
+++ b/cli/tests/integration/npm_tests.rs
@@ -433,6 +433,13 @@ itest!(types_no_types_entry {
   exit_code: 1,
 });
 
+itest!(types_d_ext {
+  args: "check --all npm/d_ext/main.ts",
+  output: "npm/d_ext/main.out",
+  envs: env_vars_for_npm_tests(),
+  http_server: true,
+});
+
 itest!(typescript_file_in_package {
   args: "run npm/typescript_file_in_package/main.ts",
   output: "npm/typescript_file_in_package/main.out",
diff --git a/cli/tests/testdata/npm/d_ext/main.out b/cli/tests/testdata/npm/d_ext/main.out
new file mode 100644
index 0000000000..e96c6e3920
--- /dev/null
+++ b/cli/tests/testdata/npm/d_ext/main.out
@@ -0,0 +1,3 @@
+Download http://localhost:4545/npm/registry/@denotest/d-ext
+Download http://localhost:4545/npm/registry/@denotest/d-ext/1.0.0.tgz
+Check file:///[WILDCARD]/npm/d_ext/main.ts
diff --git a/cli/tests/testdata/npm/d_ext/main.ts b/cli/tests/testdata/npm/d_ext/main.ts
new file mode 100644
index 0000000000..c92dbe0659
--- /dev/null
+++ b/cli/tests/testdata/npm/d_ext/main.ts
@@ -0,0 +1,3 @@
+import { test } from "npm:@denotest/d-ext";
+
+console.log(test);
diff --git a/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/index.d.ts b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/index.d.ts
new file mode 100644
index 0000000000..47326c0f62
--- /dev/null
+++ b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/index.d.ts
@@ -0,0 +1 @@
+export const test: typeof import("./types.d").value;
diff --git a/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/index.js b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/index.js
new file mode 100644
index 0000000000..62b353f3d6
--- /dev/null
+++ b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/index.js
@@ -0,0 +1 @@
+module.exports.test = 5;
diff --git a/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/package.json b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/package.json
new file mode 100644
index 0000000000..a0702a56b4
--- /dev/null
+++ b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "d-ext",
+  "version": "1.0.0",
+  "main": "./index.js"
+}
\ No newline at end of file
diff --git a/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/types.d.ts b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/types.d.ts
new file mode 100644
index 0000000000..dedc54b038
--- /dev/null
+++ b/cli/tests/testdata/npm/registry/@denotest/d-ext/1.0.0/types.d.ts
@@ -0,0 +1 @@
+export const value: 5;
diff --git a/ext/node/resolution.rs b/ext/node/resolution.rs
index 22ab47ce64..cbe9f643f9 100644
--- a/ext/node/resolution.rs
+++ b/ext/node/resolution.rs
@@ -1378,7 +1378,9 @@ fn is_relative_specifier(specifier: &str) -> bool {
 /// Alternate `PathBuf::with_extension` that will handle known extensions
 /// more intelligently.
 fn with_known_extension(path: &Path, ext: &str) -> PathBuf {
-  const NON_DECL_EXTS: &[&str] = &["cjs", "js", "json", "jsx", "mjs", "tsx"];
+  const NON_DECL_EXTS: &[&str] = &[
+    "cjs", "js", "json", "jsx", "mjs", "tsx", /* ex. types.d */ "d",
+  ];
   const DECL_EXTS: &[&str] = &["cts", "mts", "ts"];
 
   let file_name = match path.file_name() {