diff --git a/src/_shims/formdata.js b/src/_shims/formdata.js
index a3debe98..8cbe41c4 100644
--- a/src/_shims/formdata.js
+++ b/src/_shims/formdata.js
@@ -3,7 +3,15 @@
  */
 
 exports.FormData = FormData;
-exports.File = File;
 exports.Blob = Blob;
+exports.File =
+  typeof File !== 'undefined' ? File : (
+    // Bun doesn't implement File yet, so just make a shim that throws a helpful error message
+    class File extends Blob {
+      constructor() {
+        throw new Error(`file uploads aren't supported in this environment yet as 'File' is not defined`);
+      }
+    }
+  );
 
 exports.isPolyfilled = false;
diff --git a/src/_shims/formdata.mjs b/src/_shims/formdata.mjs
index 2871d130..3ee740bd 100644
--- a/src/_shims/formdata.mjs
+++ b/src/_shims/formdata.mjs
@@ -3,9 +3,18 @@
  */
 
 const _FormData = FormData;
-const _File = File;
 const _Blob = Blob;
 
+const _File =
+  typeof File !== 'undefined' ? File : (
+    // Bun doesn't implement File yet, so just make a shim that throws a helpful error message
+    class File extends Blob {
+      constructor() {
+        throw new Error(`file uploads aren't supported in this environment yet as 'File' is not defined`);
+      }
+    }
+  );
+
 export { _FormData as FormData, _File as File, _Blob as Blob };
 
 export const isPolyfilled = false;