A sentence interpretation experiment based on Bates and MacWhinney's Competition Model was administered to L2 learners of English and Chinese at three different stages of learning. The main purposes of the research were (a) to examine how transfer patterns at the sentence processing level change as a function of proficiency and (b) to investigate whether or how transfer patterns found in Chinese EFL learners (i.e., native speakers of a semantics-based language learning a syntax-centered target language) differ from those found in English CFL learners (i.e., native speakers of a syntax-based language acquiring a semantics-centered one). The results show that transfer patterns do vary as a function of proficiency, and that Chinese EFL learners and English CFL learners display somewhat different patterns of developmental change in sentence processing transfer.