diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b81120a..1032e1e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -75,6 +75,7 @@ jobs:
         if: contains(matrix.os, 'macos')
         run: |
           brew info tcl-tk
+          brew install tkinter
           coverage erase
           coverage run -a --source ./imshowtk -m pytest -v -s ./tests/
           coverage report -m