diff --git a/imgviz/_io/opencv.py b/imgviz/_io/opencv.py
index a37c939..e69ff28 100644
--- a/imgviz/_io/opencv.py
+++ b/imgviz/_io/opencv.py
@@ -1,7 +1,7 @@
 try:
     import cv2
 except ImportError:
-    cv2 = None
+    cv2 = None  # type: ignore
 import numpy as np  # NOQA
 
 
diff --git a/imgviz/resize.py b/imgviz/resize.py
index 487241b..2d2da53 100644
--- a/imgviz/resize.py
+++ b/imgviz/resize.py
@@ -6,7 +6,7 @@
 try:
     import cv2
 except ImportError:
-    cv2 = None
+    cv2 = None  # type: ignore
 
 
 def _resize_pillow(src, height, width, interpolation):