diff --git a/numcodecs/compat.py b/numcodecs/compat.py
index 52827ca6..a239e838 100644
--- a/numcodecs/compat.py
+++ b/numcodecs/compat.py
@@ -6,6 +6,7 @@
 import array
 
 
+import cupy as cp
 import numpy as np
 
 
@@ -48,8 +49,8 @@ def ensure_ndarray(buf):
 
     """
 
-    if isinstance(buf, np.ndarray):
-        # already a numpy array
+    if isinstance(buf, (np.ndarray, cp.ndarray)):
+        # already an array
         arr = buf
 
     elif isinstance(buf, array.array) and buf.typecode in 'cu':
@@ -151,6 +152,12 @@ def ensure_bytes(buf):
         if arr.dtype == object:
             raise TypeError('object arrays are not supported')
 
+        # Force CuPy arrays to NumPy arrays
+        # because they don't have a `tobytes` method (yet)
+        # xref: https://github.com/cupy/cupy/pull/2617
+        if isinstance(arr, cp.ndarray):
+            arr = arr.get()
+
         # create bytes
         buf = arr.tobytes(order='A')
 
@@ -160,6 +167,12 @@ def ensure_bytes(buf):
 def ensure_text(s, encoding='utf-8'):
     if not isinstance(s, text_type):
         s = ensure_contiguous_ndarray(s)
+
+        # Force CuPy arrays to NumPy arrays
+        # as they support the buffer protocol
+        if isinstance(s, cp.ndarray):
+            s = s.get()
+
         s = codecs.decode(s, encoding)
     return s