It has long been acknowledged that growing up in poverty is associated with a host of developmental risks, particularly in the domain of language. The effects of SES on vocabulary have been well studied, yet we know less about the degree to which SES may affect syntactic development. While it is acknowledged that syntactic development is largely guided by innate predispositions, in this talk I present evidence of SES differences in five-year-old children’s performance on a standardized measure of syntax, as well as introduce one potential explanation for these SES effects: children’s sentence processing using the test case of passive versus active sentence interpretations. Five-year-old children often interpret passive sentences as actives and their non-adultlike performance may simply reflect the dominance of actives relative to passives in their input. Additionally, I present evidence suggesting that these difficulties may also stem from characteristics of passive constructions that are difficult for children to process. Using this processing-based account, I will discuss data from a study designed to examine how children’s passive sentence interpretations, and particularly their ability to revise an initial misinterpretation, may be one mechanism that can explain differences in syntactic performance as a function of SES.