The present study compares the processing of unambiguous restrictive and non-restrictive relative clauses (RCs) within both a null context and a supportive discourse using a self-paced reading methodology. Individuals read restrictive RCs more slowly than non-restrictive RCs in a null context, but processed restrictive RCs faster than non-restrictive RCs in supportive context, resulting in an interaction between context and RC type. These results provide evidence for two theoretical points. First, principles analogous to those in referential theory [Altmann G. T. M., & Steedman, M. (1988). Interaction with context during human sentence processing. Cognition, 30, 191-238; Crain, S., & Steedman, M. (1985). On not being led up the garden path: The use of context by the psychological parser. In D. Dowty, L. Karttunnen, A. Zwicky (Eds.), Natural language parsing. Cambridge, UK: Cambridge University Press] apply not only in resolving ambiguity but also in processing unambiguous sentences. Second, the discourse context can guide and facilitate interpretive processing. This result suggests that intrasentential factors such as syntax are not autonomous from contextual processing, contrary to the modularity hypothesis [Fodor, J. A. (1983). Modularity of mind. Cambridge, MA: MIT Press].