diff --git a/ObjectiveGit/GTIndexEntry.h b/ObjectiveGit/GTIndexEntry.h
index 1e2f26d33..16b89a588 100644
--- a/ObjectiveGit/GTIndexEntry.h
+++ b/ObjectiveGit/GTIndexEntry.h
@@ -80,7 +80,7 @@ NS_ASSUME_NONNULL_BEGIN
 /// error - will be filled if an error occurs
 ///
 /// Returns this entry as a GTObject or nil if an error occurred.
-- (GTObject *)GTObject:(NSError **)error;
+- (nullable GTObject *)GTObject:(NSError **)error;
 
 @end