diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 613a773775..2afddf58d1 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -377,7 +377,7 @@ jobs:
       # Run Complement
       - run: |
           set -o pipefail
-          go test -v -json -p 1 -tags synapse_blacklist,msc2403,msc2716,msc3030 ./tests/... 2>&1 | gotestfmt
+          go test -v -json -tags synapse_blacklist,msc2403,msc2716,msc3030 ./tests/... 2>&1 | gotestfmt
         shell: bash
         name: Run Complement Tests
         env:
diff --git a/changelog.d/12283.misc b/changelog.d/12283.misc
new file mode 100644
index 0000000000..e9f2208500
--- /dev/null
+++ b/changelog.d/12283.misc
@@ -0,0 +1 @@
+Re-enable Complement concurrency in CI.