In order to identify the causes of inflectional variability in adult second-language (L2) acquisition, this study investigates lexical and syntactic aspects of gender processing in real-time L2 production and comprehension. Twenty advanced to near-native adult first language (L1) English speakers of L2 German and 20 native controls were tested in a study comprising two experiments. In elicited production, we probe accuracy in lexical gender assignment. In a visual-world eye tracking task, we test the predictive processing of syntactic gender agreement between determiners and nouns. The findings show clear contingencies (1) between overall accuracy in lexical gender assignment in production and target predictive processing of syntactic gender agreement in comprehension and (2) between the speed of lexical access and predictive syntactic gender agreement. These findings support lexical and computational accounts of L2 inflectional variability and argue against models positing representational deficits in morphosyntax in late L2 acquisition and processing. (Contains 7 tables, 3 figures and 2 notes.)