diff --git a/tox.ini b/tox.ini
index a6071bd6d..de314c3bf 100644
--- a/tox.ini
+++ b/tox.ini
@@ -22,7 +22,7 @@ passenv =
     TMPDIR
 conda_deps =
     asdf>=2.7,!=2.10.0
-    astropy=6.1.4
+    astropy==6.1.4
     astroquery>=0.4
     astroscrappy>=1.1
     bokeh>=3.0