diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0529e5dde..d78d72a6a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -70,7 +70,7 @@ jobs:
         shell: python
       - name: Test
         run: |
-            pip install numpy ml_dtypes
+            pip install "numpy<2" ml_dtypes
             cargo test --all-features
         # Not on PyPy, because no embedding API
         if: ${{ !startsWith(matrix.python-version, 'pypy') }}
@@ -104,7 +104,7 @@ jobs:
         continue-on-error: true
       - uses: taiki-e/install-action@valgrind
       - run: |
-            pip install numpy ml_dtypes
+            pip install "numpy<2" ml_dtypes
             cargo test --all-features --release
         env:
           CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER: valgrind --leak-check=no --error-exitcode=1
@@ -119,7 +119,7 @@ jobs:
         continue-on-error: true
       - uses: taiki-e/install-action@cargo-careful
       - run: |
-            pip install numpy ml_dtypes
+            pip install "numpy<2" ml_dtypes
             cargo careful test --all-features
 
   check-msrv:
@@ -195,7 +195,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install numpy
-        run: pip install numpy ml_dtypes
+        run: pip install "numpy<2" ml_dtypes
       - uses: Swatinem/rust-cache@v2
         continue-on-error: true
       - uses: dtolnay/rust-toolchain@stable
diff --git a/examples/linalg/noxfile.py b/examples/linalg/noxfile.py
index 6154c9517..291b0b1a2 100644
--- a/examples/linalg/noxfile.py
+++ b/examples/linalg/noxfile.py
@@ -3,6 +3,6 @@
 
 @nox.session
 def tests(session):
-    session.install("pip", "numpy", "pytest")
+    session.install("pip", "numpy<2", "pytest")
     session.run("pip", "install", ".", "-v")
     session.run("pytest")
diff --git a/examples/parallel/noxfile.py b/examples/parallel/noxfile.py
index 6154c9517..291b0b1a2 100644
--- a/examples/parallel/noxfile.py
+++ b/examples/parallel/noxfile.py
@@ -3,6 +3,6 @@
 
 @nox.session
 def tests(session):
-    session.install("pip", "numpy", "pytest")
+    session.install("pip", "numpy<2", "pytest")
     session.run("pip", "install", ".", "-v")
     session.run("pytest")
diff --git a/examples/simple/noxfile.py b/examples/simple/noxfile.py
index 6154c9517..291b0b1a2 100644
--- a/examples/simple/noxfile.py
+++ b/examples/simple/noxfile.py
@@ -3,6 +3,6 @@
 
 @nox.session
 def tests(session):
-    session.install("pip", "numpy", "pytest")
+    session.install("pip", "numpy<2", "pytest")
     session.run("pip", "install", ".", "-v")
     session.run("pytest")