The “Not Just Right Experience” (NJRE) has been identified as a core motivator of obsessive–compulsive behavior. Individuals high in obsessive–compulsive tendencies (OCT) have demonstrated deficits in executive functions, including working memory, set shifting, and inhibitory control, yet the role of NJREs in these deficits remains unclear. Across two experiments, we examined whether NJREs contribute to OCT-related executive-function impairments. In Experiment 1, participants completed an NJRE induction or control task, followed by working memory (Backward Digit Span), set-shifting (Digit Symbol Substitution), and inhibitory control (Stroop) tasks, a prospective metacognition test, and the Vancouver Obsessive–Compulsive Inventory. NJREs moderated the link between OCT and working memory and mediated the link between OCT and set shifting. No effects were found for inhibitory control or prospective metacognition. Experiment 2 replicated the mediation result for set shifting. These findings indicate that NJREs are robustly related to set-shifting performance among individuals with higher obsessive–compulsive tendencies, underscoring the potential utility of targeting NJREs in cognitive-behavioural intervention.