Movement is essential for everyday life and closely related to cognitive skills. The aim of the current research was to investigate whether different aspects of physical activity, i.e., aerobic fitness and motor skills, contribute above and beyond each other to the variance in children's executive functioning. Children aged 8-13 years (N = 129, 58 females, M; age;  = 10.7 years, SD; age;  = 1.6 years) participated in the current cross-sectional study. Aerobic fitness was assessed by the Progressive Aerobic Cardiovascular Endurance Run (PACER). Motor skills were assessed using the standardized Movement Assessment Battery for Children 2nd edition (M-ABC-2), including fine motor skills, balance skills, and object control. Components of executive functions (inhibition, switching, updating) were assessed using the following tasks: an animal Stroop task, a local-global task, and a 2n-back task. Hierarchical regressions were conducted to analyze the relative importance of aerobic fitness and motor skills for children's executive functions. Results indicated that aerobic fitness and fine motor skills were significantly related to switching and updating, whereas relations to inhibition were non-significant. Furthermore, it was found that fine motor skills explained additional variance above aerobic fitness in switching and updating whereas aerobic fitness did not add additional variance above fine motor skills in switching and updating. Balance and object control skills were not related to the three core executive functions. Results support the notion that aerobic fitness and fine motor skills are differently related to executive functions and highlight the importance of considering multiple components of constructs in future research.