The cognitive processing similarities between music and language is an emerging field of study, with research finding evidence for shared processing pathways in the brain, especially in relation to syntax. This research combines theory from the shared syntactic integration resource hypothesis (SSIRH; Patel, 2008) and syntactic working memory (SWM) theory (Kljajevic, 2010), and suggests there will be shared processing costs when music and language concurrently access SWM. To examine this, word lists and complex sentences were paired with three music conditions: normal; syntactic manipulation (out-of-key chord); and a control condition with an instrument manipulation. As predicted, memory for sentences declined when paired with the syntactic manipulation compared to the other two music manipulations, but the same pattern did not occur in word lists. This suggests that both sentences and music with a syntactic irregularity are accessing SWM. Word lists, however, are thought to be primarily accessing the phonological loop, and therefore did not show effects of shared processing. Musicians performed differently from non-musicians, suggesting that the processing of musical and linguistic syntax differs with musical ability. Such results suggest a separation in processing between the phonological loop and SWM, and give evidence for shared processing mechanisms between music and language syntax.