diff --git a/README.md b/README.md
index f498466a..9e569681 100644
--- a/README.md
+++ b/README.md
@@ -252,7 +252,7 @@ curl -H "x-retry-test-id: 1d05c20627844214a9ff7cbcf696317d" "http://localhost:91
 | return-broken-stream                      | [HTTP] Testbench will fail after a few downloaded bytes <br> [GRPC] Testbench will fail with `UNAVAILABLE` after a few downloaded bytes
 | return-broken-stream-after-YK             | [HTTP] Testbench will fail after YKiB of downloaded data <br> [GRPC] Testbench will fail with `UNAVAILABLE` after YKiB of downloaded data
 | return-reset-connection                   | [HTTP] Testbench will fail with a reset connection <br> [GRPC] Testbench will fail the RPC with `UNAVAILABLE`
-| stall-for-Ts-after-YK                     | [HTTP] Testbench will stall for T second after reading YKiB of downloaded data, e.g. stall-for-10s-after-12K stalls after reading 12KiB of data <br> [GRPC] Not supported
+| stall-for-Ts-after-YK                     | [HTTP] Testbench will stall for T second after reading YKiB of downloaded/uploaded data, e.g. stall-for-10s-after-12K stalls after reading/writing 12KiB of data <br> [GRPC] Not supported
 
 ## Releasing the testbench
 
@@ -264,4 +264,4 @@ Steps:
 1. Title "v0.x.x"
 1. Click Generate release notes
 1. Make sure "Set as the latest release" is checked
-1. Click "Publish Release" to release
+1. Click "Publish Release" to release
\ No newline at end of file
diff --git a/testbench/common.py b/testbench/common.py
index 678a5d82..5f7399ca 100644
--- a/testbench/common.py
+++ b/testbench/common.py
@@ -844,11 +844,17 @@ def handle_retry_test_instruction(database, request, socket_closer, method):
     broken_stream_after_bytes = (
         testbench.common.retry_return_broken_stream_after_bytes.match(next_instruction)
     )
+    if broken_stream_after_bytes and method == "storage.objects.get":
+        items = list(broken_stream_after_bytes.groups())
+        after_bytes = int(items[0]) * 1024
+        return __get_streamer_response_fn(
+            database, method, socket_closer, test_id, limit=after_bytes
+        )
 
     retry_stall_after_bytes_matches = testbench.common.retry_stall_after_bytes.match(
         next_instruction
     )
-    if retry_stall_after_bytes_matches:
+    if retry_stall_after_bytes_matches and method != "storage.objects.insert":
         items = list(retry_stall_after_bytes_matches.groups())
         stall_time = int(items[0])
         after_bytes = int(items[1]) * 1024
@@ -856,12 +862,6 @@ def handle_retry_test_instruction(database, request, socket_closer, method):
             database, method, test_id, limit=after_bytes, stall_time_sec=stall_time
         )
 
-    if broken_stream_after_bytes and method == "storage.objects.get":
-        items = list(broken_stream_after_bytes.groups())
-        after_bytes = int(items[0]) * 1024
-        return __get_streamer_response_fn(
-            database, method, socket_closer, test_id, limit=after_bytes
-        )
     retry_return_short_response = testbench.common.retry_return_short_response.match(
         next_instruction
     )
@@ -895,6 +895,30 @@ def wrapper(*args, **kwargs):
     return retry_test
 
 
+def get_stall_uploads_after_bytes(database, request, context=None, transport="HTTP"):
+    """Retrieve stall time and #bytes corresponding to uploads from retry test instructions."""
+    method = "storage.objects.insert"
+    test_id = request.headers.get("x-retry-test-id", None)
+    if not test_id:
+        return 0, 0, ""
+    next_instruction = None
+    if database.has_instructions_retry_test(test_id, method, transport=transport):
+        next_instruction = database.peek_next_instruction(test_id, method)
+    if not next_instruction:
+        return 0, 0, ""
+
+    stall_after_byte_matches = testbench.common.retry_stall_after_bytes.match(
+        next_instruction
+    )
+    if stall_after_byte_matches:
+        items = list(stall_after_byte_matches.groups())
+        stall_time = int(items[0])
+        after_bytes = int(items[1]) * 1024
+        return stall_time, after_bytes, test_id
+
+    return 0, 0, ""
+
+
 def get_retry_uploads_error_after_bytes(
     database, request, context=None, transport="HTTP"
 ):
@@ -919,9 +943,29 @@ def get_retry_uploads_error_after_bytes(
         error_code = int(items[0])
         after_bytes = int(items[1]) * 1024
         return error_code, after_bytes, test_id
+
     return 0, 0, ""
 
 
+def handle_stall_uploads_after_bytes(
+    upload,
+    data,
+    database,
+    stall_time,
+    after_bytes,
+    test_id=0,
+):
+    """
+    Handle stall-after-bytes instructions for resumable uploads.
+    Stall happens after given value of bytes.
+    e.g. We are uploading 120K of data then, stall-2s-after-100K will stall the request.
+    """
+    if len(upload.media) <= after_bytes and len(upload.media) + len(data) > after_bytes:
+        if test_id:
+            database.dequeue_next_instruction(test_id, "storage.objects.insert")
+        time.sleep(stall_time)
+
+
 def handle_retry_uploads_error_after_bytes(
     upload,
     data,
diff --git a/testbench/rest_server.py b/testbench/rest_server.py
index 96308406..72a0ae88 100644
--- a/testbench/rest_server.py
+++ b/testbench/rest_server.py
@@ -16,6 +16,7 @@
 import datetime
 import json
 import logging
+import time
 
 import flask
 from google.protobuf import json_format
@@ -978,6 +979,18 @@ def object_insert(bucket_name):
         blob, projection = gcs_type.object.Object.init_media(flask.request, bucket)
     elif upload_type == "multipart":
         blob, projection = gcs_type.object.Object.init_multipart(flask.request, bucket)
+        # Handle stall for full uploads.
+        testbench.common.extract_instruction(request, context=None)
+        (
+            stall_time,
+            after_bytes,
+            test_id,
+        ) = testbench.common.get_stall_uploads_after_bytes(db, request)
+        if stall_time and len(blob.media) >= after_bytes:
+            if test_id:
+                db.dequeue_next_instruction(test_id, "storage.objects.insert")
+            time.sleep(stall_time)
+
     db.insert_object(
         bucket_name,
         blob,
@@ -1104,6 +1117,23 @@ def resumable_upload_chunk(bucket_name):
                 chunk_last_byte,
                 test_id,
             )
+
+        testbench.common.extract_instruction(request, context=None)
+        (
+            stall_time,
+            after_bytes,
+            test_id,
+        ) = testbench.common.get_stall_uploads_after_bytes(db, request)
+
+        if stall_time:
+            testbench.common.handle_stall_uploads_after_bytes(
+                upload,
+                data,
+                db,
+                stall_time,
+                after_bytes,
+                test_id,
+            )
         # The testbench should ignore any request bytes that have already been persisted,
         # to be aligned with GCS behavior (https://cloud.google.com/storage/docs/resumable-uploads#resent-data).
         # Thus we validate chunk_first_byte against last_byte_persisted.
diff --git a/tests/test_testbench_retry.py b/tests/test_testbench_retry.py
index a5b5f8a1..0030993e 100644
--- a/tests/test_testbench_retry.py
+++ b/tests/test_testbench_retry.py
@@ -30,6 +30,7 @@
 import testbench
 from google.storage.v2 import storage_pb2
 from testbench import rest_server
+from tests.format_multipart_upload import format_multipart_upload
 
 UPLOAD_QUANTUM = 256 * 1024
 
@@ -655,6 +656,230 @@ def test_retry_test_return_error_after_bytes(self):
         self.assertIn("size", create_rest)
         self.assertEqual(int(create_rest.get("size")), 2 * UPLOAD_QUANTUM)
 
+    def test_write_retry_test_stall_after_bytes(self):
+        # Create a new bucket
+        response = self.client.post(
+            "/storage/v1/b", data=json.dumps({"name": "bucket-name"})
+        )
+        self.assertEqual(response.status_code, 200)
+
+        # Setup a stall for reading back the object.
+        response = self.client.post(
+            "/retry_test",
+            data=json.dumps(
+                {
+                    "instructions": {
+                        "storage.objects.insert": [
+                            "stall-for-1s-after-250K",
+                            "stall-for-1s-after-300K",
+                        ]
+                    }
+                }
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, 200)
+        self.assertTrue(
+            response.headers.get("content-type").startswith("application/json")
+        )
+
+        create_rest = json.loads(response.data)
+        self.assertIn("id", create_rest)
+        test_id = create_rest.get("id")
+
+        # Initiate resumable upload
+        response = self.client.post(
+            "/upload/storage/v1/b/bucket-name/o",
+            query_string={"uploadType": "resumable", "name": "stall"},
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, 200)
+
+        location = response.headers.get("location")
+        self.assertIn("upload_id=", location)
+        match = re.search(r"[&?]upload_id=([^&]+)", location)
+        self.assertIsNotNone(match, msg=location)
+        upload_id = match.group(1)
+
+        # Upload the first 256KiB chunk of data and trigger the stall.
+        chunk = self._create_block(UPLOAD_QUANTUM)
+        self.assertEqual(len(chunk), UPLOAD_QUANTUM)
+
+        start_time = time.perf_counter()
+        response = self.client.put(
+            f"/upload/storage/v1/b/bucket-name/o",
+            query_string={"upload_id": upload_id},
+            headers={
+                "content-range": "bytes 0-{len:d}/{obj_size:d}".format(
+                    len=UPLOAD_QUANTUM - 1, obj_size=2 * UPLOAD_QUANTUM
+                ),
+                "x-retry-test-id": test_id,
+            },
+            data=chunk,
+        )
+        end_time = time.perf_counter()
+        elapsed_time = end_time - start_time
+        self.assertGreater(elapsed_time, 1)
+        self.assertEqual(response.status_code, 308)
+
+        # Upload the second 256KiB chunk of data and trigger the stall again.
+        start_time = time.perf_counter()
+        chunk = self._create_block(UPLOAD_QUANTUM)
+        self.assertEqual(len(chunk), UPLOAD_QUANTUM)
+        response = self.client.put(
+            "/upload/storage/v1/b/bucket-name/o",
+            query_string={"upload_id": upload_id},
+            headers={
+                "content-range": "bytes 0-{len:d}/{obj_size:d}".format(
+                    len=2 * UPLOAD_QUANTUM - 1, obj_size=2 * UPLOAD_QUANTUM
+                ),
+                "x-retry-test-id": test_id,
+            },
+            data=chunk,
+        )
+        end_time = time.perf_counter()
+        elapsed_time = end_time - start_time
+        self.assertGreater(elapsed_time, 1)
+        self.assertEqual(response.status_code, 200, msg=response.data)
+
+        # Upload the second 256KiB chunk of data and check that stall not happen
+        start_time = time.perf_counter()
+        chunk = self._create_block(UPLOAD_QUANTUM)
+        self.assertEqual(len(chunk), UPLOAD_QUANTUM)
+        response = self.client.put(
+            "/upload/storage/v1/b/bucket-name/o",
+            query_string={"upload_id": upload_id},
+            headers={
+                "content-range": "bytes 0-{len:d}/{obj_size:d}".format(
+                    len=2 * UPLOAD_QUANTUM - 1, obj_size=2 * UPLOAD_QUANTUM
+                ),
+                "x-retry-test-id": test_id,
+            },
+            data=chunk,
+        )
+        end_time = time.perf_counter()
+        elapsed_time = end_time - start_time
+        self.assertLess(elapsed_time, 1)
+        self.assertEqual(response.status_code, 200, msg=response.data)
+
+    def test_write_retry_test_stall_single_shot(self):
+        # Create a new bucket
+        response = self.client.post(
+            "/storage/v1/b", data=json.dumps({"name": "bucket-name"})
+        )
+        self.assertEqual(response.status_code, 200)
+
+        # Setup a stall for reading back the object.
+        response = self.client.post(
+            "/retry_test",
+            data=json.dumps(
+                {
+                    "instructions": {
+                        "storage.objects.insert": [
+                            "stall-for-1s-after-250K",
+                        ]
+                    }
+                }
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, 200)
+        self.assertTrue(
+            response.headers.get("content-type").startswith("application/json")
+        )
+
+        create_rest = json.loads(response.data)
+        self.assertIn("id", create_rest)
+        test_id = create_rest.get("id")
+
+        # Upload the 256KiB of data and trigger the stall.
+        data = self._create_block(UPLOAD_QUANTUM)
+        self.assertEqual(len(data), UPLOAD_QUANTUM)
+
+        start_time = time.perf_counter()
+        boundary, payload = format_multipart_upload({}, data)
+        response = self.client.post(
+            "/upload/storage/v1/b/bucket-name/o",
+            query_string={"uploadType": "multipart", "name": "stall"},
+            content_type="multipart/related; boundary=" + boundary,
+            headers={
+                "x-retry-test-id": test_id,
+            },
+            data=payload,
+        )
+        end_time = time.perf_counter()
+        elapsed_time = end_time - start_time
+        self.assertEqual(response.status_code, 200)
+        self.assertGreater(elapsed_time, 1)
+
+        # Upload the data again and check that stall not happen.
+        start_time = time.perf_counter()
+        response = self.client.post(
+            "/upload/storage/v1/b/bucket-name/o",
+            query_string={"uploadType": "multipart", "name": "stall"},
+            content_type="multipart/related; boundary=" + boundary,
+            headers={
+                "x-retry-test-id": test_id,
+            },
+            data=payload,
+        )
+        end_time = time.perf_counter()
+        elapsed_time = end_time - start_time
+        self.assertLess(elapsed_time, 1)
+        self.assertEqual(response.status_code, 200)
+
+    def test_write_retry_test_stall_single_shot_while_upload_size_less_than_stall_size(
+        self,
+    ):
+        # Create a new bucket
+        response = self.client.post(
+            "/storage/v1/b", data=json.dumps({"name": "bucket-name"})
+        )
+        self.assertEqual(response.status_code, 200)
+
+        # Setup a stall for reading back the object.
+        response = self.client.post(
+            "/retry_test",
+            data=json.dumps(
+                {
+                    "instructions": {
+                        "storage.objects.insert": [
+                            "stall-for-1s-after-250K",
+                        ]
+                    }
+                }
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, 200)
+        self.assertTrue(
+            response.headers.get("content-type").startswith("application/json")
+        )
+
+        create_rest = json.loads(response.data)
+        self.assertIn("id", create_rest)
+        test_id = create_rest.get("id")
+
+        # Upload the 200KiB of data and check stall not happen.
+        data = self._create_block(200 * 1024)
+        self.assertEqual(len(data), 200 * 1024)
+
+        start_time = time.perf_counter()
+        boundary, payload = format_multipart_upload({}, data)
+        response = self.client.post(
+            "/upload/storage/v1/b/bucket-name/o",
+            query_string={"uploadType": "multipart", "name": "stall"},
+            content_type="multipart/related; boundary=" + boundary,
+            headers={
+                "x-retry-test-id": test_id,
+            },
+            data=payload,
+        )
+        end_time = time.perf_counter()
+        elapsed_time = end_time - start_time
+        self.assertEqual(response.status_code, 200)
+        self.assertLess(elapsed_time, 1)
+
 
 class TestTestbenchRetryGrpc(unittest.TestCase):
     def setUp(self):