diff --git a/fvcore/__init__.py b/fvcore/__init__.py
index 1d78872..4fcde7e 100644
--- a/fvcore/__init__.py
+++ b/fvcore/__init__.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 # This line will be programatically read/write by setup.py.
 # Leave them at the bottom of this file and don't touch them.
 __version__ = "0.1.6"
diff --git a/fvcore/common/__init__.py b/fvcore/common/__init__.py
index 5c7f19c..5276b67 100644
--- a/fvcore/common/__init__.py
+++ b/fvcore/common/__init__.py
@@ -1 +1,3 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
diff --git a/fvcore/common/benchmark.py b/fvcore/common/benchmark.py
index 6bc3b8e..d624253 100644
--- a/fvcore/common/benchmark.py
+++ b/fvcore/common/benchmark.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 # pyre-ignore-all-errors[2,3]
 import sys
 import time
diff --git a/fvcore/common/checkpoint.py b/fvcore/common/checkpoint.py
index 5f87a03..ef86e81 100644
--- a/fvcore/common/checkpoint.py
+++ b/fvcore/common/checkpoint.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 # pyre-ignore-all-errors[2,3,58]
 
 import logging
diff --git a/fvcore/common/config.py b/fvcore/common/config.py
index 3882b09..cef5ba9 100644
--- a/fvcore/common/config.py
+++ b/fvcore/common/config.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import logging
 import os
 from typing import Any, Callable, Dict, IO, List, Union
diff --git a/fvcore/common/download.py b/fvcore/common/download.py
index e7b1a4b..82c0cb1 100644
--- a/fvcore/common/download.py
+++ b/fvcore/common/download.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 from iopath.common.download import download
 
 
diff --git a/fvcore/common/file_io.py b/fvcore/common/file_io.py
index 31250e1..ec39790 100644
--- a/fvcore/common/file_io.py
+++ b/fvcore/common/file_io.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import logging
 import os
 import tempfile
diff --git a/fvcore/common/history_buffer.py b/fvcore/common/history_buffer.py
index ae6ecd3..3cae8bc 100644
--- a/fvcore/common/history_buffer.py
+++ b/fvcore/common/history_buffer.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 from typing import List, Optional, Tuple
 
 import numpy as np
diff --git a/fvcore/common/param_scheduler.py b/fvcore/common/param_scheduler.py
index f95350b..9042981 100644
--- a/fvcore/common/param_scheduler.py
+++ b/fvcore/common/param_scheduler.py
@@ -1,3 +1,4 @@
+# pyre-strict
 import bisect
 import math
 from typing import List, Optional, Sequence, Union
diff --git a/fvcore/common/registry.py b/fvcore/common/registry.py
index a0ae0f1..5a6634c 100644
--- a/fvcore/common/registry.py
+++ b/fvcore/common/registry.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+
+# pyre-strict
 # pyre-ignore-all-errors[2,3]
 from typing import Any, Dict, Iterable, Iterator, Tuple
 
diff --git a/fvcore/common/timer.py b/fvcore/common/timer.py
index 3de4a16..6bf3e8a 100644
--- a/fvcore/common/timer.py
+++ b/fvcore/common/timer.py
@@ -1,6 +1,8 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 # -*- coding: utf-8 -*-
 
+# pyre-strict
+
 from time import perf_counter
 from typing import Optional
 
diff --git a/fvcore/nn/__init__.py b/fvcore/nn/__init__.py
index e00306e..34f6631 100644
--- a/fvcore/nn/__init__.py
+++ b/fvcore/nn/__init__.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-ignore-all-errors
 from .activation_count import activation_count, ActivationCountAnalysis
 from .flop_count import flop_count, FlopCountAnalysis
 from .focal_loss import (
diff --git a/fvcore/nn/activation_count.py b/fvcore/nn/activation_count.py
index 6ce543f..1983b41 100644
--- a/fvcore/nn/activation_count.py
+++ b/fvcore/nn/activation_count.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 # pyre-ignore-all-errors[2,33]
 
 from collections import defaultdict
diff --git a/fvcore/nn/distributed.py b/fvcore/nn/distributed.py
index 4852d07..a726745 100644
--- a/fvcore/nn/distributed.py
+++ b/fvcore/nn/distributed.py
@@ -1,3 +1,4 @@
+# pyre-strict
 from typing import List, Tuple
 
 import torch
diff --git a/fvcore/nn/flop_count.py b/fvcore/nn/flop_count.py
index ac21f61..aa6c606 100644
--- a/fvcore/nn/flop_count.py
+++ b/fvcore/nn/flop_count.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 # pyre-ignore-all-errors[2,33]
 
 from collections import defaultdict
diff --git a/fvcore/nn/focal_loss.py b/fvcore/nn/focal_loss.py
index 23b3f71..ec48190 100644
--- a/fvcore/nn/focal_loss.py
+++ b/fvcore/nn/focal_loss.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import torch
 from torch.nn import functional as F
 
diff --git a/fvcore/nn/giou_loss.py b/fvcore/nn/giou_loss.py
index 377358d..6ba14e8 100644
--- a/fvcore/nn/giou_loss.py
+++ b/fvcore/nn/giou_loss.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import torch
 
 
diff --git a/fvcore/nn/jit_analysis.py b/fvcore/nn/jit_analysis.py
index d2cf61f..0d815ef 100644
--- a/fvcore/nn/jit_analysis.py
+++ b/fvcore/nn/jit_analysis.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+
+# pyre-strict
 # pyre-ignore-all-errors[2,33]
 
 import logging
diff --git a/fvcore/nn/jit_handles.py b/fvcore/nn/jit_handles.py
index 747205c..a498f82 100644
--- a/fvcore/nn/jit_handles.py
+++ b/fvcore/nn/jit_handles.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+
+# pyre-strict
 # pyre-ignore-all-errors[2,3,16,33,6,23]
 # NOTE: most Any type in this file should be torch._C.Value - which was not yet annotated.
 # pyre also doesn't work well with many Optional in this file
diff --git a/fvcore/nn/parameter_count.py b/fvcore/nn/parameter_count.py
index b5a3193..07d2628 100644
--- a/fvcore/nn/parameter_count.py
+++ b/fvcore/nn/parameter_count.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
 
+# pyre-strict
+
 import typing
 from collections import defaultdict
 
diff --git a/fvcore/nn/precise_bn.py b/fvcore/nn/precise_bn.py
index 012fcc5..ff184f9 100644
--- a/fvcore/nn/precise_bn.py
+++ b/fvcore/nn/precise_bn.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 # pyre-ignore-all-errors[2,6,16]
 
 import itertools
diff --git a/fvcore/nn/print_model_statistics.py b/fvcore/nn/print_model_statistics.py
index 5c45d28..b04ea43 100644
--- a/fvcore/nn/print_model_statistics.py
+++ b/fvcore/nn/print_model_statistics.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 from collections import defaultdict
 from typing import Any, Dict, Iterable, List, Optional, Set, Tuple
 
diff --git a/fvcore/nn/smooth_l1_loss.py b/fvcore/nn/smooth_l1_loss.py
index 9e25db6..e8bf43d 100644
--- a/fvcore/nn/smooth_l1_loss.py
+++ b/fvcore/nn/smooth_l1_loss.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import torch
 
 
diff --git a/fvcore/nn/squeeze_excitation.py b/fvcore/nn/squeeze_excitation.py
index 42227d4..f50745a 100644
--- a/fvcore/nn/squeeze_excitation.py
+++ b/fvcore/nn/squeeze_excitation.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 from typing import Optional
 
 import torch
diff --git a/fvcore/nn/weight_init.py b/fvcore/nn/weight_init.py
index b6444bf..10c24ff 100644
--- a/fvcore/nn/weight_init.py
+++ b/fvcore/nn/weight_init.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import torch.nn as nn
 
 
diff --git a/fvcore/transforms/__init__.py b/fvcore/transforms/__init__.py
index 53a303d..8b6eb52 100644
--- a/fvcore/transforms/__init__.py
+++ b/fvcore/transforms/__init__.py
@@ -1,3 +1,5 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 from .transform import *
diff --git a/io_tests/test_file_io.py b/io_tests/test_file_io.py
index 26bb845..dceb8cc 100644
--- a/io_tests/test_file_io.py
+++ b/io_tests/test_file_io.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import os
 import shutil
 import tempfile
diff --git a/tests/__init__.py b/tests/__init__.py
index 5c7f19c..5276b67 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1 +1,3 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
diff --git a/tests/bm_common.py b/tests/bm_common.py
index faf559c..80df6ca 100644
--- a/tests/bm_common.py
+++ b/tests/bm_common.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 from fvcore.common.benchmark import benchmark
 from test_common import TestHistoryBuffer
 
diff --git a/tests/bm_focal_loss.py b/tests/bm_focal_loss.py
index 6544fc9..d0af9f5 100644
--- a/tests/bm_focal_loss.py
+++ b/tests/bm_focal_loss.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import torch
 from fvcore.common.benchmark import benchmark
 from test_focal_loss import TestFocalLoss, TestFocalLossStar
diff --git a/tests/bm_main.py b/tests/bm_main.py
index c63885f..964fff2 100755
--- a/tests/bm_main.py
+++ b/tests/bm_main.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python3
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import glob
 import importlib
 import sys
diff --git a/tests/param_scheduler/test_scheduler_composite.py b/tests/param_scheduler/test_scheduler_composite.py
index 730f61a..c65c69b 100644
--- a/tests/param_scheduler/test_scheduler_composite.py
+++ b/tests/param_scheduler/test_scheduler_composite.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import copy
 import unittest
 
diff --git a/tests/param_scheduler/test_scheduler_constant.py b/tests/param_scheduler/test_scheduler_constant.py
index 5a63bb1..f6b2a93 100644
--- a/tests/param_scheduler/test_scheduler_constant.py
+++ b/tests/param_scheduler/test_scheduler_constant.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import unittest
 
 from fvcore.common.param_scheduler import ConstantParamScheduler
diff --git a/tests/param_scheduler/test_scheduler_cosine.py b/tests/param_scheduler/test_scheduler_cosine.py
index b7306f1..0da68b5 100644
--- a/tests/param_scheduler/test_scheduler_cosine.py
+++ b/tests/param_scheduler/test_scheduler_cosine.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import copy
 import unittest
 
diff --git a/tests/param_scheduler/test_scheduler_exponential.py b/tests/param_scheduler/test_scheduler_exponential.py
index 4c94b97..7adff52 100644
--- a/tests/param_scheduler/test_scheduler_exponential.py
+++ b/tests/param_scheduler/test_scheduler_exponential.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import unittest
 
 from fvcore.common.param_scheduler import ExponentialParamScheduler
diff --git a/tests/param_scheduler/test_scheduler_linear.py b/tests/param_scheduler/test_scheduler_linear.py
index 2eb8e41..764f352 100644
--- a/tests/param_scheduler/test_scheduler_linear.py
+++ b/tests/param_scheduler/test_scheduler_linear.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import unittest
 
 from fvcore.common.param_scheduler import LinearParamScheduler
diff --git a/tests/param_scheduler/test_scheduler_multi_step.py b/tests/param_scheduler/test_scheduler_multi_step.py
index c3462da..d1e24f6 100644
--- a/tests/param_scheduler/test_scheduler_multi_step.py
+++ b/tests/param_scheduler/test_scheduler_multi_step.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import copy
 import unittest
 
diff --git a/tests/param_scheduler/test_scheduler_polynomial.py b/tests/param_scheduler/test_scheduler_polynomial.py
index db18af0..22e54ea 100644
--- a/tests/param_scheduler/test_scheduler_polynomial.py
+++ b/tests/param_scheduler/test_scheduler_polynomial.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import unittest
 
 from fvcore.common.param_scheduler import PolynomialDecayParamScheduler
diff --git a/tests/param_scheduler/test_scheduler_step.py b/tests/param_scheduler/test_scheduler_step.py
index 979c9f2..b85477b 100644
--- a/tests/param_scheduler/test_scheduler_step.py
+++ b/tests/param_scheduler/test_scheduler_step.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import copy
 import unittest
 from typing import Any, Dict
diff --git a/tests/param_scheduler/test_scheduler_step_with_fixed_gamma.py b/tests/param_scheduler/test_scheduler_step_with_fixed_gamma.py
index d22c56c..1ddde94 100644
--- a/tests/param_scheduler/test_scheduler_step_with_fixed_gamma.py
+++ b/tests/param_scheduler/test_scheduler_step_with_fixed_gamma.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates.
 
+# pyre-ignore-all-errors
+
 import copy
 import unittest
 
diff --git a/tests/test_activation_count.py b/tests/test_activation_count.py
index b716f07..c87a4e2 100644
--- a/tests/test_activation_count.py
+++ b/tests/test_activation_count.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 # pyre-ignore-all-errors[2]
 
 import typing
diff --git a/tests/test_checkpoint.py b/tests/test_checkpoint.py
index 85f2412..537ce71 100644
--- a/tests/test_checkpoint.py
+++ b/tests/test_checkpoint.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import copy
 import os
 import random
diff --git a/tests/test_common.py b/tests/test_common.py
index 7554e80..6d27070 100644
--- a/tests/test_common.py
+++ b/tests/test_common.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import math
 import time
 import typing
diff --git a/tests/test_flop_count.py b/tests/test_flop_count.py
index 8ab7eeb..a871379 100644
--- a/tests/test_flop_count.py
+++ b/tests/test_flop_count.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 # pyre-ignore-all-errors[2,3,14,53]
 import typing
 import unittest
diff --git a/tests/test_focal_loss.py b/tests/test_focal_loss.py
index 435ef54..1e2e6bf 100644
--- a/tests/test_focal_loss.py
+++ b/tests/test_focal_loss.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import typing
 import unittest
 
diff --git a/tests/test_giou_loss.py b/tests/test_giou_loss.py
index 24ca0dc..b8606b6 100644
--- a/tests/test_giou_loss.py
+++ b/tests/test_giou_loss.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import unittest
 
 import numpy as np
diff --git a/tests/test_jit_model_analysis.py b/tests/test_jit_model_analysis.py
index 529c6b9..e300dc9 100644
--- a/tests/test_jit_model_analysis.py
+++ b/tests/test_jit_model_analysis.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+
+# pyre-strict
 # pyre-ignore-all-errors[2,56]
 
 import logging
diff --git a/tests/test_layers_squeeze_excitation.py b/tests/test_layers_squeeze_excitation.py
index db090c9..da9204a 100644
--- a/tests/test_layers_squeeze_excitation.py
+++ b/tests/test_layers_squeeze_excitation.py
@@ -1,4 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# pyre-strict
 import itertools
 import unittest
 from typing import Iterable
diff --git a/tests/test_param_count.py b/tests/test_param_count.py
index 7f4464d..64482bd 100644
--- a/tests/test_param_count.py
+++ b/tests/test_param_count.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 
 import unittest
 
diff --git a/tests/test_precise_bn.py b/tests/test_precise_bn.py
index e150b4c..2558112 100644
--- a/tests/test_precise_bn.py
+++ b/tests/test_precise_bn.py
@@ -1,6 +1,8 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 # -*- coding: utf-8 -*-
 
+# pyre-strict
+
 import itertools
 import unittest
 from typing import List, Tuple
diff --git a/tests/test_print_model_statistics.py b/tests/test_print_model_statistics.py
index 9a5ea59..67d33e1 100644
--- a/tests/test_print_model_statistics.py
+++ b/tests/test_print_model_statistics.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
 
+# pyre-strict
+
 import unittest
 from typing import Dict
 
diff --git a/tests/test_smooth_l1_loss.py b/tests/test_smooth_l1_loss.py
index f6e1bfc..4d361bb 100644
--- a/tests/test_smooth_l1_loss.py
+++ b/tests/test_smooth_l1_loss.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import unittest
 
 import numpy as np
diff --git a/tests/test_transform_util.py b/tests/test_transform_util.py
index 5189681..bf10967 100644
--- a/tests/test_transform_util.py
+++ b/tests/test_transform_util.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import unittest
 
 import numpy as np
diff --git a/tests/test_weight_init.py b/tests/test_weight_init.py
index ba1164b..4d26ffd 100644
--- a/tests/test_weight_init.py
+++ b/tests/test_weight_init.py
@@ -1,5 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 
+# pyre-strict
+
 import itertools
 import math
 import unittest