Background <p>Research on the relationship between personality traits and sleep problems is crucial, as it informs interventions designed to improve mental health and overall well-being. This meta-analytic review aimed to examine the associations between the Big Five personality traits and both subjective sleep quality and insomnia severity. Another objective was to compare the mean scores of personality traits in individuals with insomnia and healthy controls.</p> Method <p>Three international databases were systematically searched for articles published in English between January 1990 and November 2022 (PROSPERO-CRD42022378352). Due to the observed heterogeneity, pooled estimates of correlations and standardized mean differences were calculated using the random-effects method. Meta-regression and subgroup analyses were performed to identify potential moderators.</p> Results <p>The estimates derived from 51 studies (involving nearly 31,000 participants from 20 countries) indicated that higher scores of neuroticism and lower scores of extraversion, openness, agreeableness, and conscientiousness were significantly associated with poor sleep quality (<i>r</i> =  − 0.05 to 0.31). With the exception of openness, all other personality traits were significant correlates of insomnia. The meta-regressions revealed that population type, geographic region, age, sample size, sample ratio, quality of study, and year of study served as significant moderators.</p> Conclusion <p>Despite the significant associations between most personality traits and sleep problems, the heterogeneous estimates were influenced by several moderators. Addressing these moderators can provide researchers with deeper insights into personalized interventions aimed at improving sleep quality across diverse populations. These significant associations also underscore the importance of incorporating personality assessments in clinical settings for individuals experiencing sleep disturbances.</p>