The goal of this research was to examine the relationship between executive functions and personality traits and the moderating role that playing sport activity in this connection. The research was conducted on a sample of 214 people, among whom there were 70 who practice sports professionally, i.e. those who train very regularly (five or more times a week) and are involved in sports competitions, 73 who practice sports amateurly, i.e. train regularly (two to four times a week) a sport without the intention of participating in competitions, and 71 who do not play sports, that is, do not practice any sport or are not regularly (less than twice a week) involved in physical activity. The Executive Skills Questionnaire-Revised (ESQ–R) (Strait et al., 2020) was used to measure executive functions, and the Croatian version of the Big Five Inventory (BFI; Kardum et al., 2006) was used to measure personality traits. Correlation analysis showed that executive functions were negatively related to emotional instability, positively related to agreeableness, conscientiousness and extraversion, while only some measures of executive functions were significantly related to openness. Examination of the moderating role of playing sports in the relationship between executive functions and personality traits showed that the degree of playing sports statistically significantly moderates only the relationship between conscientiousness and the ability to manage plans and emotional instability and the ability to regulate emotions. So, it is evident that there are indications that athletes may have different patterns of reaction to stimuli, especially in the aforementioned connections, but this connection has not yet been sufficiently clarified. The results of this research indicate that the field of executive function research in general, but also in the context of sports, is extremely demanding and additional research needs to be carried out in order to deepen knowledge.