diff --git a/packages/@uppy/aws-s3/src/S3Uploader.ts b/packages/@uppy/aws-s3/src/S3Uploader.ts
index e6c4f44dc..ce493d226 100644
--- a/packages/@uppy/aws-s3/src/S3Uploader.ts
+++ b/packages/@uppy/aws-s3/src/S3Uploader.ts
@@ -294,14 +294,24 @@ export default class S3Uploader<M extends Meta, B extends Body> {
     }
 
     this.#key = key
+    this.#uploadId = uploadId
+
+    // The file may have been removed/cancelled while createMultipartUpload was
+    // in flight. We deliberately don't pass the abort signal into the create
+    // request: if it were cancelled mid-flight, S3 might still create the upload
+    // while we never receive the uploadId — an orphan we couldn't clean up.
+    // Instead we let create finish, then abort the upload in S3 so it isn't left
+    // behind, and skip persisting resume state for a cancelled upload.
+    if (this.#abortController?.signal.aborted) {
+      this.abort()
+      return
+    }
 
     // Persist resume state so Golden Retriever can restore it after page refresh
     this.#options.uppy.setFileState(this.#options.file.id, {
       s3Multipart: { uploadId, key },
     })
 
-    this.#uploadId = uploadId
-
     await this.#uploadRemainingParts()
   }
 
diff --git a/packages/@uppy/aws-s3/tests/index.test.ts b/packages/@uppy/aws-s3/tests/index.test.ts
index c52ebf176..db334e658 100644
--- a/packages/@uppy/aws-s3/tests/index.test.ts
+++ b/packages/@uppy/aws-s3/tests/index.test.ts
@@ -374,6 +374,72 @@ describe('AwsS3', () => {
       expect(result).toBeDefined()
       expect(result?.successful).toHaveLength(0)
     })
+
+    it('aborts the multipart upload in S3 if the file is removed during createMultipartUpload', async () => {
+      const operations: string[] = []
+      let markCreateStarted!: () => void
+      const createStarted = new Promise<void>((r) => {
+        markCreateStarted = r
+      })
+      let releaseCreate!: () => void
+      const createGate = new Promise<void>((r) => {
+        releaseCreate = r
+      })
+
+      const signRequest = vi.fn(async (req: any) => {
+        const params = new URLSearchParams()
+        if (req.uploadId) params.set('uploadId', req.uploadId)
+        params.set('method', req.method)
+        return {
+          url: `https://test-bucket.s3.us-east-1.amazonaws.com/${req.key}?${params}`,
+        }
+      })
+
+      server.use(
+        http.post(s3Url, async ({ request }) => {
+          const hasUploadId = new URL(request.url).searchParams.has('uploadId')
+          if (!hasUploadId) {
+            operations.push('createMultipart')
+            markCreateStarted()
+            await createGate // hang create until the test releases it
+            return new HttpResponse(
+              s3Responses.createMultipart('upload-1', 'test-key'),
+              { status: 200, headers: { 'Content-Type': 'application/xml' } },
+            )
+          }
+          operations.push('completeMultipart')
+          return new HttpResponse('', { status: 200 })
+        }),
+        http.delete(s3Url, () => {
+          operations.push('abortMultipart')
+          return new HttpResponse('', { status: 204 })
+        }),
+      )
+
+      const core = new Core().use(AwsS3, {
+        s3Endpoint: 'https://test-bucket.s3.us-east-1.amazonaws.com',
+        region: 'us-east-1',
+        signRequest,
+        shouldUseMultipart: true,
+      })
+      core.addFile({
+        source: 'test',
+        name: 'big.bin',
+        type: 'application/octet-stream',
+        data: new File([new Uint8Array(6 * MB)], 'big.bin'),
+      })
+      const fileId = Object.keys(core.getState().files)[0]
+
+      const uploadPromise = core.upload()
+      await createStarted // createMultipartUpload is now in flight
+      core.removeFile(fileId) // cancel while create is pending
+      releaseCreate() // let create finish so S3 returns the uploadId
+      await uploadPromise
+
+      // The create succeeded server-side, so the now-orphaned upload must be
+      // aborted in S3 rather than left behind.
+      await vi.waitFor(() => expect(operations).toContain('abortMultipart'))
+    })
   })
 
   describe('Golden Retriever resume state (s3Multipart)', () => {