This study compared working memory ability in multilingual young adults and their monolingual peers on four components of working memory (verbal and visuospatial storage, verbal and visuospatial processing). The sample comprised 39 monolingual English speakers, and 39 multilinguals, who spoke an African language as their first and third languages, and English as their second language, all with high levels of proficiency. The multilingual young adults came from lower socioeconomic status (SES) backgrounds and possessed smaller English vocabularies than the monolinguals, features which make this group an under-researched population. Both when SES and verbal ability were and were not statistically controlled, there was evidence of a multilingual advantage in all of the working memory components, which was most pronounced in visuospatial processing. These findings support evidence from bilinguals showing cognitive advantages beyond inhibitory control, and suggest that multilingualism may influence the executive control system generally.