diff --git a/.github/workflows/latest_deps.yml b/.github/workflows/latest_deps.yml
index 1a61d179d905..41da1c74088c 100644
--- a/.github/workflows/latest_deps.yml
+++ b/.github/workflows/latest_deps.yml
@@ -38,6 +38,8 @@ jobs:
       # `pip install matrix-synapse[all]` as closely as possible.
       - run: poetry update --no-dev
       - run: poetry run pip list > after.txt && (diff -u before.txt after.txt || true)
+      - name: Remove warn_unused_ignores from mypy config
+        run: sed '/warn_unused_ignores = True/d' -i mypy.ini
       - run: poetry run mypy
   trial:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/twisted_trunk.yml b/.github/workflows/twisted_trunk.yml
index 8fc1affb7746..5f0671f3503a 100644
--- a/.github/workflows/twisted_trunk.yml
+++ b/.github/workflows/twisted_trunk.yml
@@ -24,6 +24,8 @@ jobs:
           poetry remove twisted
           poetry add --extras tls git+https://github.com/twisted/twisted.git#trunk
           poetry install --no-interaction --extras "all test"
+      - name: Remove warn_unused_ignores from mypy config
+        run: sed '/warn_unused_ignores = True/d' -i mypy.ini
       - run: poetry run mypy
 
   trial: