diff --git a/.github/workflows/osx.yml b/.github/workflows/osx.yml
index 09d594949..a449423e3 100644
--- a/.github/workflows/osx.yml
+++ b/.github/workflows/osx.yml
@@ -24,7 +24,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install OS dependencies
       run: |
-        brew install llvm@11 tesseract
+        brew install llvm@11 tesseract tesserat-lang
         python -m pip install --upgrade pip
         LLVM_CONFIG=/usr/local/Cellar/llvm@11/11.1.0/bin/llvm-config pip install llvmlite
     - name: Install Mathics3 with full Python dependencies