This study tests native Brazilian Portuguese (BP) speakers of second language (L2) Spanish in the domain of phonologically null object pronouns. This is a worthwhile first language (L1)-L2 pairing given that these languages are historically and typologically related and both seemingly allow for object drop. Nevertheless, the underlying syntax of phonologically null object pronouns is distinct in each language, resulting in differences in their respective syntactic reflexes. We pursue whether or not it is more difficult to acquire new syntactic structure for a L2 property that, on the surface, is shared by the L1. In other words, we explore whether advanced BP learners of L2 Spanish will be successful in the acquisition of Spanish object drop to the same degree as English learners and European Portuguese learners who were previously shown by Bruhn de Garavito and Guijarro-Fuentes (2001) to be quite successful. By means of a scalar grammaticality judgment task with context, we examine competence of the Spanish restrictions on the distribution of dropped objects that differ from BP in various syntactic positions (e.g., simple clauses vs. strong islands) while alternating the Spanish-specific semantic variable of definiteness as determined by the context. The data show that the semantic alternations are acquired as well as the new syntax; however, such acquisition does not guarantee preemption of the L1 syntactic option, which may result in target-deviant variability. We discuss the data in light of what they bring to bear on questions pertinent to formal SLA theory.