This study presents evidence of advanced second language (L2) learners' syntactic gap processing in processing sentences with scrambling in Japanese. The data from probe recognition and self-paced reading experiments indicate that Korean learners engaged in syntactic gap processing in processing moderately demanding scrambling but did not in processing highly taxing scrambling. English learners exhibited first language transfer effects. The findings of the study are consistent with a working hypothesis that L2 syntactic gap processing is severely constrained by limitations on cognitive resources available during L2 processing. The findings contradict the view that L2 gap processing is verb-driven.