diff --git a/CHANGELOG.md b/CHANGELOG.md
index ace08f4ee68..7fd0b2e4c58 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -30,6 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed a mispelling: the parameter `contructor_extras` in `Lazy()` is now correctly called `constructor_extras`.
 - Fixed broken links in `allennlp.nn.initializers` docs.
 - `TransformerTextField` can now take tensors of shape `(1, n)` like the tensors produced from a HuggingFace tokenizer.
+- `tqdm` lock is now set inside `MultiProcessDataLoading` when new workers are spawned to avoid contention when writing output.
 - `ConfigurationError` is now pickleable.
 
 ### Changed
diff --git a/allennlp/common/tqdm.py b/allennlp/common/tqdm.py
index bad9f35b574..dc9692a96ee 100644
--- a/allennlp/common/tqdm.py
+++ b/allennlp/common/tqdm.py
@@ -88,3 +88,11 @@ def tqdm(*args, **kwargs):
         }
 
         return _tqdm(*args, **new_kwargs)
+
+    @staticmethod
+    def set_lock(lock):
+        _tqdm.set_lock(lock)
+
+    @staticmethod
+    def get_lock():
+        return _tqdm.get_lock()
diff --git a/allennlp/data/data_loaders/multiprocess_data_loader.py b/allennlp/data/data_loaders/multiprocess_data_loader.py
index a46ea4f4f53..6243144f5aa 100644
--- a/allennlp/data/data_loaders/multiprocess_data_loader.py
+++ b/allennlp/data/data_loaders/multiprocess_data_loader.py
@@ -428,20 +428,22 @@ def _iter_batches(self) -> Iterator[TensorDict]:
                 self._join_workers(workers, queue)
 
     def _start_instance_workers(self, queue: mp.JoinableQueue, ctx) -> List[BaseProcess]:
+        Tqdm.set_lock(mp.RLock())
         workers: List[BaseProcess] = []
         for worker_id in range(self.num_workers):
             worker: BaseProcess = ctx.Process(
-                target=self._instance_worker, args=(worker_id, queue), daemon=True
+                target=self._instance_worker, args=(worker_id, queue, Tqdm.get_lock()), daemon=True
             )
             worker.start()
             workers.append(worker)
         return workers
 
     def _start_batch_workers(self, queue: mp.JoinableQueue, ctx) -> List[BaseProcess]:
+        Tqdm.set_lock(mp.RLock())
         workers: List[BaseProcess] = []
         for worker_id in range(self.num_workers):
             worker: BaseProcess = ctx.Process(
-                target=self._batch_worker, args=(worker_id, queue), daemon=True
+                target=self._batch_worker, args=(worker_id, queue, Tqdm.get_lock()), daemon=True
             )
             worker.start()
             workers.append(worker)
@@ -463,7 +465,8 @@ def _join_workers(self, workers: List[BaseProcess], queue) -> None:
             if worker.is_alive():
                 worker.terminate()
 
-    def _instance_worker(self, worker_id: int, queue: mp.JoinableQueue) -> None:
+    def _instance_worker(self, worker_id: int, queue: mp.JoinableQueue, lock) -> None:
+        Tqdm.set_lock(lock)
         try:
             self.reader._set_worker_info(WorkerInfo(self.num_workers, worker_id))
             instances = self.reader.read(self.data_path)
@@ -495,7 +498,8 @@ def _instance_worker(self, worker_id: int, queue: mp.JoinableQueue) -> None:
         # Wait until this process can safely exit.
         queue.join()
 
-    def _batch_worker(self, worker_id: int, queue: mp.JoinableQueue) -> None:
+    def _batch_worker(self, worker_id: int, queue: mp.JoinableQueue, lock) -> None:
+        Tqdm.set_lock(lock)
         try:
             self.reader._set_worker_info(WorkerInfo(self.num_workers, worker_id))
             instances = self.reader.read(self.data_path)