diff --git a/src/create-module-declaration.js b/src/create-module-declaration.js
index dcb940d..4336df7 100644
--- a/src/create-module-declaration.js
+++ b/src/create-module-declaration.js
@@ -12,7 +12,7 @@ import { clean_jsdoc, get_dts, is_declaration, is_reference, resolve_dts, walk }
  * @returns {{
  *   content: string;
  *   mappings: Map<string, import('./types').Mapping>;
- *   ambient: string[];
+ *   ambient: import('./types').ModuleReference[];
  * }}
  */
 export function create_module_declaration(id, entry, created, resolve) {
@@ -21,7 +21,7 @@ export function create_module_declaration(id, entry, created, resolve) {
 	/** @type {Map<string, import('./types').Mapping>} */
 	const mappings = new Map();
 
-	/** @type {string[]} */
+	/** @type {import('./types').ModuleReference[]} */
 	const ambient = [];
 
 	/** @type {Record<string, Record<string, import('./types').Declaration>>} */
@@ -73,9 +73,7 @@ export function create_module_declaration(id, entry, created, resolve) {
 			}
 
 			for (const dep of module.ambient_imports) {
-				if (!dep.external) {
-					ambient.push(dep.id);
-				}
+				ambient.push(dep);
 			}
 
 			for (const binding of module.imports.values()) {
diff --git a/src/index.js b/src/index.js
index 67c808b..4ae51b8 100644
--- a/src/index.js
+++ b/src/index.js
@@ -90,6 +90,9 @@ export async function createBundle(options) {
 		/** @type {Set<string>} */
 		const ambient_modules = new Set();
 
+		/** @type {Set<string>} */
+		const external_ambient_modules = new Set();
+
 		let first = true;
 
 		/**
@@ -125,8 +128,12 @@ export async function createBundle(options) {
 
 			types += content;
 			all_mappings.set(id, mappings);
-			for (const id of ambient) {
-				ambient_modules.add(id);
+			for (const dep of ambient) {
+				if (dep.external) {
+					external_ambient_modules.add(dep.id);
+				} else {
+					ambient_modules.add(dep.id);
+				}
 			}
 		}
 
@@ -152,6 +159,14 @@ export async function createBundle(options) {
 			types += result.trim().toString();
 		}
 
+		if (external_ambient_modules.size > 0) {
+			const imports = Array.from(external_ambient_modules)
+				.map((id) => `import '${id}';`)
+				.join('\n');
+
+			types = `${imports}\n\n${types}`;
+		}
+
 		// finally, add back exports as appropriate
 		const ast = ts.createSourceFile(output, types, ts.ScriptTarget.Latest, false, ts.ScriptKind.TS);
 		const magic_string = new MagicString(types);
diff --git a/test/samples/ambient-imports/input/types.d.ts b/test/samples/ambient-imports/input/types.d.ts
new file mode 100644
index 0000000..73ff6d7
--- /dev/null
+++ b/test/samples/ambient-imports/input/types.d.ts
@@ -0,0 +1,3 @@
+import 'some-ambient-import';
+
+export interface Foo {}
diff --git a/test/samples/ambient-imports/output/index.d.ts b/test/samples/ambient-imports/output/index.d.ts
new file mode 100644
index 0000000..9bb8f94
--- /dev/null
+++ b/test/samples/ambient-imports/output/index.d.ts
@@ -0,0 +1,7 @@
+import 'some-ambient-import';
+
+declare module 'ambient-imports' {
+	export interface Foo {}
+}
+
+//# sourceMappingURL=index.d.ts.map
\ No newline at end of file
diff --git a/test/samples/ambient-imports/output/index.d.ts.map b/test/samples/ambient-imports/output/index.d.ts.map
new file mode 100644
index 0000000..ff6baf1
--- /dev/null
+++ b/test/samples/ambient-imports/output/index.d.ts.map
@@ -0,0 +1,14 @@
+{
+	"version": 3,
+	"file": "index.d.ts",
+	"names": [
+		"Foo"
+	],
+	"sources": [
+		"../input/types.d.ts"
+	],
+	"sourcesContent": [
+		null
+	],
+	"mappings": ";;;kBAEiBA,GAAGA"
+}
\ No newline at end of file