diff --git a/.github/workflows/ci-code.yml b/.github/workflows/ci-code.yml
index bc047ab216..e5f4dce13d 100644
--- a/.github/workflows/ci-code.yml
+++ b/.github/workflows/ci-code.yml
@@ -94,6 +94,13 @@ jobs:
       if: matrix.python-version == 3.5
       run: pip install -I setuptools==42.0.0  # Minimally required version for Python 3.5.
 
+    # Work-around issue caused by pymatgen's setup process, which will install the latest
+    # numpy version (including release candidates) regardless of our actual specification
+    # By installing the version from the requirements file, we should get a compatible version
+    - name: Install numpy
+      run: |
+        pip install `grep 'numpy==' requirements/requirements-py-${{ matrix.python-version }}.txt`
+
     - name: Install aiida-core
       run: |
         pip install --use-feature=2020-resolver -r requirements/requirements-py-${{ matrix.python-version }}.txt
diff --git a/.github/workflows/test-install.yml b/.github/workflows/test-install.yml
index b1d2603af7..d70b5393a7 100644
--- a/.github/workflows/test-install.yml
+++ b/.github/workflows/test-install.yml
@@ -153,6 +153,13 @@ jobs:
 
     - run: pip install --upgrade pip
 
+    # Work-around issue caused by pymatgen's setup process, which will install the latest
+    # numpy version (including release candidates) regardless of our actual specification
+    # By installing the version from the requirements file, we should get a compatible version
+    - name: Install numpy
+      run: |
+        pip install `grep 'numpy==' requirements/requirements-py-${{ matrix.python-version }}.txt`
+
     - name: upgrade setuptools [py35]
       if: matrix.python-version == 3.5
       run: pip install -I setuptools==42.0.0