A variety of studies have reported that learners of English as a second language find subject relative clauses easier to produce and comprehend than direct object relatives, but it is unclear whether this preference should be attributed to structural factors or to a linear distance effect. This paper seeks to resolve this issue and to extend our understanding of SLA in general by investigating the interpretation of subject and direct object relative clauses by English-speaking learners of Korean, a left-branching language in which subject gaps in relative clauses are more distant from the head than are object gaps. The results of a comprehension task conducted with 53 beginning and intermediate learners point toward a strong preference for subject relative clauses, favoring the structural account.