diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f4c15ee4..dd3ec227 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        numpy-version: ["oldest-supported-numpy", "numpy"]
+        numpy-version: ["oldest-supported-numpy", "'numpy<2'"]
         python-version: ["3.7", "3.8", "3.9", "3.10"]
     steps:
     - name: Checkout code
diff --git a/requirements.txt b/requirements.txt
index 24a9b6e8..3e98c385 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 cython>=0.28
-numpy>=1.14
+numpy>=1.14,<2.0
 scipy
 matplotlib
 raysect==0.8.1
diff --git a/setup.py b/setup.py
index 6cf51624..eb56a797 100644
--- a/setup.py
+++ b/setup.py
@@ -115,7 +115,7 @@
     long_description=long_description,
     long_description_content_type="text/markdown",
     install_requires=[
-        "numpy>=1.14",
+        "numpy>=1.14,<2.0",
         "scipy",
         "matplotlib",
         "raysect==0.8.1",