Sedivy (2002) proposed that using "only" and prior referential context to specify contrastive focus can guide the parsing of relative clause ambiguities. We report two studies investigating this hypothesis, using sentences that either temporarily allowed or disallowed a transitive main clause interpretation. Sentence completions demonstrated that "only" and interrogative contexts jointly influenced the frequency of relative clause completions to ambiguous fragments. Eye-tracking demonstrated that conjoint effects of "only" and context influenced initial parsing decisions only when the active transitive analysis was unavailable. The results are consistent with previous observations that the influence of contrastive focus on sentence processing depends on which syntactic analyses are available to the parser (Liversedge, Paterson, & Clayes, 2002; Paterson, Liversedge, & Underwood, 1999).