Mandarin sortal classifiers simultaneously encode semantic and grammatical form class cues. Building on a second language (L2) study of Grüter et al. we used the same visual world eye-tracking experiment, designed to examine the relative use of the two cues, testing Mandarin heritage speakers (HSs) living in an English-speaking environment. Given the importance of understanding individual differences, the present study also examined if/how individual HSs may systematically differ as a function of experience with Mandarin. As a group, HSs – like the first language (L1) group in Grüter et al.’s study – showed a clear reliance on the grammatical form class cue. Nevertheless, individual HSs with Mandarin schooling and with more Mandarin social exposure/use showed more reliance on semantics, the L2 pattern observed in Grüter et al. We discuss why this latter pattern might have obtained (formal and informal literacy), while highlighting the value of individual difference approaches to understanding HS processing.