This meta-analysis synthesized 35 English studies (130 effect sizes, N = 1,981) that employed online tasks to investigate the processing of multiword sequences (MWSs). We examined (a) to what extent MWSs enjoy a processing advantage over novel word combinations; (b) how such a processing advantage is moderated by statistical regularities (i.e., phrasal frequency, association strength), MWS type, and explicitness of experimental tasks; and (c) whether such moderating patterns differ between L1 speakers and L2 speakers. The results confirmed the processing advantage for most subtypes of MWSs, with effect sizes ranging from small to medium. For L1 speakers and L2 speakers, the processing advantage of MWSs was found across the continuum of phrasal frequency and association strength and varied. Interestingly, task explicitness moderated the processing advantage of MWSs but only for L2 speakers. Taken together, our results shed light on the understanding of MWSs as well as directions for future research.