We investigated the role of discourse context in relative clause processing. We first replicated Reali and Christiansen's (2007a) finding that pronominal object relative clauses are easier to process than analogous subject relative clauses (an effect which stands in contrast to previous research on pronominal relative clauses). We then analyzed corpus data to demonstrate that the embedded noun phrase in object relative clauses nearly always has a discourse-old referent, even if the noun phrase is not pronominal, while the referent of the embedded noun phrase in subject relative clauses is typically discourse-new. We then extended the work of Mak et al. (2008), by demonstrating in region-by-region reading that full noun phrase object relative clauses are not more difficult to process than subject relatives when they are preceded by appropriate discourse contexts. Finally, we reanalyzed data from the Dundee Eye-tracking corpus to show that contra Demberg and Keller (2007), naturally occurring object relatives are no harder to process than subject relatives. We conclude that the processing difficulties associated with object as compared to subject relative clauses arises because object relative clauses violate more discourse expectations in typical experimental contexts. (Contains 13 figures and 8 tables.)