Conscientiousness is characterized by self‐control, organization, and goal orientation and is positively related to a number of health and professional outcomes. Thus, it is commonly suggested that conscientiousness should be related to superior executive functioning (EF) abilities, especially prepotent response inhibition. However, little empirical support for this notion has emerged, perhaps due to oversimplified and underspecified modeling of EF. The current study sought to fill this gap by testing relations between conscientiousness and three facets of EF using a nested factors latent variable approach. Participants (N = 420; Mage = 22.5; 50% male; 91% Caucasian) completed a measure of conscientiousness and nine EF tasks designed to tap three related yet distinguishable facets of EF: working memory updating, mental set shifting, and prepotent response inhibition. Structural equation models showed that conscientiousness is positively associated with the EF facet of mental set shifting but not response inhibition or working memory updating. Despite the common notion that conscientiousness is associated with cognitive abilities related to rigid control over impulses (i.e., inhibition), the current results suggest the cognitive ability most associated with conscientiousness is characterized by flexibility and the ability to adapt to changing environmental contingencies and task demands.