diff --git a/Makefile b/Makefile
index 823e97c..b89d341 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,7 @@ mypy: venv/bin/mypy
 # Update CONTRIBUTING.md if these commands change
 venv/bin/mypy:
 	python -mvenv venv
-	venv/bin/pip install -r requirements.txt 'mypy!=1.7.0'
+	venv/bin/pip install -r requirements-dev.txt
 
 .PHONY: clean
 clean:
diff --git a/requirements-dev.txt b/requirements-dev.txt
new file mode 100644
index 0000000..cc76d37
--- /dev/null
+++ b/requirements-dev.txt
@@ -0,0 +1,6 @@
+# SPDX-FileCopyrightText: 2023 Jeff Epler
+#
+# SPDX-License-Identifier: MIT
+
+-r requirements.txt
+mypy