diff --git a/cpp/src/arrow/array/array_dict.h b/cpp/src/arrow/array/array_dict.h
index 0e256ec815213..24cdd3b59525c 100644
--- a/cpp/src/arrow/array/array_dict.h
+++ b/cpp/src/arrow/array/array_dict.h
@@ -91,9 +91,8 @@ class ARROW_EXPORT DictionaryArray : public Array {
   /// \param[in] dictionary the new dictionary
   /// \param[in] transpose_map transposition array of this array's indices
   ///   into the target array's indices. The value of transpose_map should
-  ///   be in the range [0, this->length()). And the dictionary array's
-  ///   indices in the target array's indices should be in the range
-  ///   of [0, dictionary->length()).
+  ///   be in the range [0, dictionary->length()). And the dictionary indices
+  ///   at transpose_map[i] should not be out of bounds.
   ///
   /// \param[in] pool a pool to allocate the array data from
   Result<std::shared_ptr<Array>> Transpose(