In this self-paced reading study, we first tested the cross-linguistic validity of the position of antecedent strategy proposed for anaphora resolution in Italian (Carminati, 2002) in a Latin American variety of Spanish. We then examined the application of this strategy by Spanish heritage speakers of the same dialect who were largely English dominant. Forty-five monolingual speakers of Mexican Spanish and 28 Spanish heritage speakers of Mexican descent read sentences in which null and overt subject pronouns were biased for and against expected antecedent biases. Our results suggest that Mexican monolinguals display distinct antecedent biases for null and overt pronouns. Furthermore, the Spanish heritage speakers, though not monolingual-like, did not violate discourse constraints on the resolution of overt pronouns, contra the findings of offline research (see Keating, VanPatten & Jegerski, 2011). We discuss the findings in terms of a processing-based account.