diff --git a/importlib_metadata/__init__.py b/importlib_metadata/__init__.py
index 9b912f8e..0d2b4e25 100644
--- a/importlib_metadata/__init__.py
+++ b/importlib_metadata/__init__.py
@@ -14,7 +14,6 @@
 import email
 import functools
 import itertools
-import json
 import operator
 import os
 import pathlib
@@ -673,6 +672,9 @@ def origin(self):
         return self._load_json('direct_url.json')
 
     def _load_json(self, filename):
+        # Deferred for performance (python/importlib_metadata#503)
+        import json
+
         return pass_none(json.loads)(
             self.read_text(filename),
             object_hook=lambda data: types.SimpleNamespace(**data),
diff --git a/newsfragments/503.feature.rst b/newsfragments/503.feature.rst
new file mode 100644
index 00000000..7e6bdc7a
--- /dev/null
+++ b/newsfragments/503.feature.rst
@@ -0,0 +1 @@
+Deferred import of json
\ No newline at end of file