In an event-related potential (ERP) study we investigated the role of age of acquisition (AoA) on the use of second language rhythmic properties during syntactic ambiguity resolution. Syntactically ambiguous sentences embedded in rhythmically regular and irregular contexts were presented to Turkish early and late second language (L2) learners of German and to German monolingual controls. Regarding rhythmic properties, Turkish is syllable-timed and prefers the iamb as its metric foot, while German is stress-timed, relying on the trochee. To utilize rhythm during the processing of syntactic ambiguity in L2, Turkish early and late L2 learners of German must master different rhythmic properties than in their first language. ERPs reveal a reduction in the P600 response to object-first sentences presented in rhythmically regular, but not in rhythmically irregular contexts for early learners and monolinguals only. No such effect was found for late L2 learners. Results indicate an interactive use of rhythmic information during the processing of syntactic ambiguity by monolinguals and early learners. Further, data from late L2 learners suggest that the acquisition of rhythmic properties may have to occur in a sensitive learning period.