Because of enduring experience of managing two languages, bilinguals have been argued to develop superior executive functioning compared with monolinguals. Despite extensive investigation, there is, however, no consensus regarding the existence of such a bilingual advantage. Here we synthesized comparisons of bilinguals' and monolinguals' performance in six executive domains using 891 effect sizes from 152 studies on adults. We also included unpublished data, and considered the potential influence of a number of study-, task-, and participant-related variables. Before correcting estimates for observed publication bias, our analyses revealed a very small bilingual advantage for inhibition, shifting, and working memory, but not for monitoring or attention. No evidence for a bilingual advantage remained after correcting for bias. For verbal fluency, our analyses indicated a small bilingual disadvantage, possibly reflecting less exposure for each individual language when using two languages in a balanced manner. Moreover, moderator analyses did not support theoretical presuppositions concerning the bilingual advantage. We conclude that the available evidence does not provide systematic support for the widely held notion that bilingualism is associated with benefits in cognitive control functions in adults. Public Significance Statement The idea that bilinguals outperform monolinguals in cognitive control functions seems to have already been accepted by the popular media and educators, because of a number of influential studies reporting a bilingual advantage. Our thorough meta-analysis, however, suggests that healthy bilingual adults do not have such a cognitive control advantage. The synthesis of 152 studies and 891 comparisons and several moderator variables does not show systematic advantages across the analyzed cognitive domains, tasks, or bilingual populations.