diff --git a/.github/workflows/swift.yml b/.github/workflows/swift.yml
index e4f08cc..dff2366 100644
--- a/.github/workflows/swift.yml
+++ b/.github/workflows/swift.yml
@@ -17,7 +17,7 @@ jobs:
     - name: Build
       run: ${{ matrix.options }} swift build -c ${{ matrix.config }}
     - name: Test
-      run: ${{ matrix.options }} swift test -c ${{ matrix.config }}
+      run: ${{ matrix.options }} swift test -c ${{ matrix.config }} --no-parallel
 
   coverage:
     name: Code Coverage
@@ -74,7 +74,7 @@ jobs:
     - name: Build
       run: ${{ matrix.options }} swift build -c ${{ matrix.config }}
     - name: Test
-      run: ${{ matrix.options }} swift test -c ${{ matrix.config }}
+      run: ${{ matrix.options }} swift test -c ${{ matrix.config }} --no-parallel
 
   skip-fuse:
       name: Skip Fuse (Android)
diff --git a/Scripts/coverage.sh b/Scripts/coverage.sh
index 80bc30a..09aace7 100755
--- a/Scripts/coverage.sh
+++ b/Scripts/coverage.sh
@@ -45,7 +45,7 @@ fi
 # 1. Run the tests with coverage instrumentation.
 if [ "${SKIP_TEST:-0}" != "1" ]; then
     echo "==> Running tests with code coverage"
-    swift test --enable-code-coverage
+    swift test --enable-code-coverage --no-parallel
 fi
 
 # 2. Locate the coverage artifacts SwiftPM produced.