This study investigated the nature of the relationship between working memory (WM) and sentence processing by examining interference effects in sentence comprehension and relating those to performance on a set of WM tasks, executive function tasks, and vocabulary tests. For online sentence comprehension, semantic interference effects were negatively correlated with semantic retention capacity. Syntactic interference effects were negatively related only to reading span. These results are consistent with the multiple capacities account (Martin & Romani, 1994), which postulates that there are separable retention abilities for semantic, syntactic, and phonological information, with the first two being critical for sentence comprehension. For offline sentence comprehension, participants with better semantic STM, WM span, vocabulary, or Stroop performance showed less difficulty in semantic interference resolution. These results were consistent to some extent with multiple capacities account, the general resources account (Just & Carpenter, 1992) and retrieval-based interference account (Van Dyke, 2007). Keywords: Interference effect, Working memory capacity, Cue-based retrieval, Sentence processing