Two experiments assessed the extent to which grammatical gender provides a predictive basis for bilinguals’ judgments about perceptual gender. In both experiments, French-English bilinguals and native English monolinguals were consecutively presented with images of objects manipulated for their (i) conceptual gender association and (ii) grammatical gender category and were instructed to make a decision on a subsequent target face. The experiments differed in the implicitness of the association between the object primes and target faces. Results revealed that when prior knowledge sources such as conceptual gender can be strategically used to resolve the immediate task (Experiment 1), this information was readily extracted and employed. However, grammatical gender demonstrated a more robust and persisting effect on the bilinguals’ judgments, indicating that the retrieval of obligatory grammatical information is automatic and modulates perceptual judgments (Experiment 2). These results suggest that grammar enables an effective and robust means to access prior knowledge which may be independent of task requirements.