How does learning a second language influence native language processing? In the present study, we examined whether knowledge of Spanish - a language that marks grammatical gender on inanimate nouns - influences lexical processing in English - a language that does not mark grammatical gender. We tested three groups of adult English native speakers: monolinguals, emergent bilinguals with high exposure to Spanish, and emergent bilinguals with low exposure to Spanish. Participants engaged in an associative learning task in English where they learned to associate names of inanimate objects with proper names. For half of the pairs, the grammatical gender of the noun's Spanish translation matched the gender of the proper name (e.g., corn-Patrick). For half of the pairs, the grammatical gender of the noun's Spanish translation mismatched the gender of the proper noun (e.g., beach-William). High-Spanish-exposure bilinguals (but not monolinguals or low-Spanish-exposure bilinguals) were less accurate at retrieving proper names for gender-incongruent than for gender-congruent pairs. This indicates that second-language morphosyntactic information is activated during native-language processing, even when the second language is acquired later in life.