In this talk, Hopp discusses the relationship between sentence processing and learning in adult L2 acquisition. acquisition. He reviews recent sentence processing and priming studies that expose adult L2 learners to input to input designed to make learners process L2 morphosyntactic detail. These studies test whether and how quickly learners adapt their processing to grammatical patterns experienced in the input. Finding that L2 speakers rapidly adapt their grammatical processing to the target input, he sketches how adaptation in L2 processing can form the basis for implicit learning of L2 morphosyntax. Hopp then discusses the limits of processing-based learning via adaptation by contrasting short-term adaptation and longer-term learning.