diff --git a/dm_control/mujoco/index.py b/dm_control/mujoco/index.py
index 76e534cc..fa0492b6 100644
--- a/dm_control/mujoco/index.py
+++ b/dm_control/mujoco/index.py
@@ -378,7 +378,7 @@ def convert_key_item(self, key_item):
         key_item = np.array([self._names_to_offsets[util.to_native_string(k)]
                              for k in key_item.flat])
         # Ensure the output shape is the same as that of the input.
-        key_item.shape = original_shape
+        key_item = key_item.reshape(original_shape)
 
     return key_item
 
diff --git a/dm_control/mujoco/index_test.py b/dm_control/mujoco/index_test.py
index 3eaeae53..736943c8 100644
--- a/dm_control/mujoco/index_test.py
+++ b/dm_control/mujoco/index_test.py
@@ -347,8 +347,9 @@ def testReadWrite_(self, field):
     # Write unique values to the FieldIndexer and read them back again.
     # Don't write to non-float fields since these might contain pointers.
     if np.issubdtype(old_contents.dtype, np.floating):
-      new_contents = np.arange(old_contents.size, dtype=old_contents.dtype)
-      new_contents.shape = old_contents.shape
+      new_contents = np.arange(
+          old_contents.size, dtype=old_contents.dtype
+      ).reshape(old_contents.shape)
       field[:] = new_contents
       np.testing.assert_array_equal(new_contents, field[:])
 
diff --git a/dm_control/mujoco/wrapper/core_test.py b/dm_control/mujoco/wrapper/core_test.py
index 3489f126..b78f8109 100644
--- a/dm_control/mujoco/wrapper/core_test.py
+++ b/dm_control/mujoco/wrapper/core_test.py
@@ -552,8 +552,9 @@ def _write_unique_values(self, attr_name, target_array):
     elif (attr_name != "stack"
           and not np.issubdtype(target_array.dtype, np.integer)
           and not np.issubdtype(target_array.dtype, np.bool_)):
-      new_contents = np.arange(target_array.size, dtype=target_array.dtype)
-      new_contents.shape = target_array.shape
+      new_contents = np.arange(
+          target_array.size, dtype=target_array.dtype
+      ).reshape(target_array.shape)
       target_array[:] = new_contents
       np.testing.assert_array_equal(new_contents, target_array[:])