diff --git a/tox.ini b/tox.ini
index 2aca8dc9c..d67610470 100644
--- a/tox.ini
+++ b/tox.ini
@@ -38,7 +38,7 @@ description =
 deps =
     cov: pytest-cov
 
-    oldestdeps: numpy==1.21.6
+    oldestdeps: numpy==1.23.5
     oldestdeps: scipy==1.3.*
     oldestdeps: astropy==5.1.*
     oldestdeps: gwcs==0.18.*