Second-language (L2) sentence processing may differ from processing in a native language in a variety of ways, and it has been argued that one major difference is that L2 learners can only construct shallow representations that lack structural details (e.g., Clahsen & Felser, 2006). The present study challenges this hypothesis by comparing the extent to which advanced L1 Spanish-L2 English learners and English native speakers make use of the relative clause island constraint in constructing filler-gap dependencies. In offline acceptability judgment and online self-paced reading experiments that used stimuli adapted from Traxler and Pickering (1996), both the L2 group and the native-speaker control group demonstrated clear evidence for application of the relative clause island constraint. These findings suggest that advanced L2 learners not only build abstract structural representations but also rapidly constrain the active search for a gap location. These results cast doubt on the proposal that L2 learners are unable to build structural representations with grammatical precision.