diff --git a/pyproject.toml b/pyproject.toml
index 969213ae..da2f8d6b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -43,7 +43,7 @@ dependencies = [
     "cryptography",
     "h5py >= 3.6.0",
     "numcodecs",
-    "numpy",
+    "numpy < 2.0.0",
     "psutil",
     "pyjwt",
     "pytz",
diff --git a/requirements.txt b/requirements.txt
index 59b2a4af..1055557f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@ bitshuffle
 cryptography
 h5py>=3.6.0
 numcodecs
-numpy
+numpy<2.0.0
 psutil
 pyjwt
 pytz