AbstractSLA research has explored the many benefits of study abroad programs. However, there is limited research that explores syntactic gains made abroad by the advanced learner and addresses the question: How does length of stay abroad affect language acquisition, particularly advanced L2 features? The present study addresses this question from a UG perspective by evaluating 31 advanced learners of Spanish L2 who spent an academic year abroad in Barcelona. The development and acquisition of the properties of the null subject parameter were measured at one month (representing a summer abroad), four months (representing a semester abroad), and nine months (representing an academic year abroad). A discussion follows on some additional factors that need to be considered when sending an advanced language learner on a study abroad program.