diff --git a/.github/workflows/matrix-and-codecov-on-merge-to-main.yml b/.github/workflows/matrix-and-codecov-on-merge-to-main.yml
index ff4f6de..ed569c5 100644
--- a/.github/workflows/matrix-and-codecov-on-merge-to-main.yml
+++ b/.github/workflows/matrix-and-codecov-on-merge-to-main.yml
@@ -42,7 +42,17 @@ jobs:
           conda config --set always_yes yes
           --set changeps1 no
 
-      - name: Install diffpy.labpdfproc and requirements
+      - name: Install diffpy.labpdfproc and requirements for Linux
+        if: runner.os == 'Linux'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libgtk-3-dev
+          conda install --file requirements/test.txt
+          pip install -r requirements/pip.txt
+          python -m pip install . --no-deps
+
+      - name: Install diffpy.labpdfproc and requirements for non-Linux
+        if: runner.os != 'Linux'
         run: |
           conda install --file requirements/test.txt
           pip install -r requirements/pip.txt
diff --git a/.github/workflows/tests-on-pr.yml b/.github/workflows/tests-on-pr.yml
index f089057..adcdb8c 100644
--- a/.github/workflows/tests-on-pr.yml
+++ b/.github/workflows/tests-on-pr.yml
@@ -32,6 +32,11 @@ jobs:
           conda config --set always_yes yes
           --set changeps1 no
 
+      - name: Install libgtk for Linux
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libgtk-3-dev
+
       - name: Install diffpy.labpdfproc and requirements
         run: |
           conda install --file requirements/test.txt