diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a59fed9..dbadf44 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -25,7 +25,7 @@ jobs:
     - uses: actions/checkout@v2
     - uses: ruby/setup-ruby@v1
       env: 
-        BUNDLE_BUILD_NOKOGIRI___C: "--use-system-libraries"
+        BUNDLE_BUILD__NOKOGIRI: "--use-system-libraries"
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true