(1) Background: In this study, we aimed to determine differences in the levels of motor competence according to biological factors (sex, age and weight status) and sociocultural factors (socioeconomic level and belonging to an indigenous people or not) in students of the La Araucanía Region, Chile. (2) Methods: A total of 552 students in 5th and 6th grade were evaluated (49.6% girls; age M = 11.3; SD = 0.8). To assess motor competence (domains of object control and self-movement), the MOBAK 5-6 test was applied. (3) Results: In the object control dimension, significant differences were found according to sex, with the boys performing higher than the girls. According to age, schoolchildren aged 11.0 to 11.9 performed higher than those aged 10.0 to 10.9, and according to socioeconomic status, schoolchildren from schools with a higher socioeconomic status showed a higher motor performance. No significant interaction effects were found between groups. With regard to the self-movement domain, statistically significant differences were only found according to weight status, where students of normal weight presented the highest performance. No significant effects were found between any of the groups. (4) Conclusions: This study shows the importance of considering the biological and sociocultural characteristics in the development of motor competence when interpreting data or planning interventions in different settings.