diff --git a/nisext/__init__.py b/nisext/__init__.py
index b556c66d13..6b19d7eb8e 100644
--- a/nisext/__init__.py
+++ b/nisext/__init__.py
@@ -4,3 +4,10 @@
 nibabel uses these routines, and houses them, and installs them.  nipy-proper
 and dipy use them.
 """
+
+import warnings
+
+warnings.warn(
+    """The nisext package is deprecated as of NiBabel 5.0 and will be fully
+removed in NiBabel 6.0"""
+)