Morphological systems arise from language experience encoded in the lexicon, which includes much statistical and episodic information (see Pierrehumbert, 2006; Rácz, Pierrehumbert, Hay, & Papp, 2015). Lexical statistics have been successfully applied in theories of morphological learning and change ( Bybee, 1995), but there remains much unexplained variation in speakers’ morphological choices and patterns of generalization. A promising route for explanation is the role of social-indexical information in shaping morphological systems. We present a quantitative experimental study on the relationship of morphological perception to speaker gender, a highly salient aspect of the linguistic context that is known to be important in language variation and change. We show that people have significant success in associating English words with speaker gender, and that their implicit knowledge generalizes to gender associations of novel words (pseudowords) on the basis of their component morphemes. By analyzing judgments of morphological decomposition in conjunction with these indexical judgments, we also make inferences about the cognitive architecture for social-indexical effects in morphology.