Research has demonstrated a close relationship between verbal short-term (STM) and working memory (WM) and receptive language in children (Baddeley, Gathercole, & Papagno, 1998; Ellis & Sinclair, 1996). Few studies have examined the relationship between memory and language production, and these studies focus on STM only. Though correlations have been found between verbal STM and production, the nature of the correlations are unclear. The current study examined the possibility that receptive language mediates the relationship between memory and language production. Children between 3;0 and 5;11 were administered tests assessing receptive vocabulary, receptive grammar, expressive vocabulary, verbal STM, and verbal WM. Additionally, transcripts from free-play sessions were used to assess grammar production. A regression based analytic approach revealed STM and WM mediate the relationship between receptive language and productive language. The existence of these mediated relationships are discussed in relation to the role of working memory in the speech output buffer.