The investigation of semantic context effects has served as a valuable tool in investigating mechanisms of language production. Classic semantic interference effects have provided influential support for and interest in a competitive lexical selection mechanism. However, recent interest in semantic facilitation effects has stimulated a discussion on whether context effects reflect competition during lexical selection. In this review we propose a framework of lexical selection by competition that is sensitive to the activation of lexical cohorts. We outline our proposal and then present a selective review of the empirical evidence, much of which has been central to the development of alternative non-competitive models. We suggest that by adopting the assumptions of our proposal we can parsimoniously account for a majority of the discussed semantic facilitation and interference effects.