This study examined the relationship among sex, body mass index, motor skill competence (MSC), perceived physical competence (PPC), and school-day physical activity in preschool students (N = 34). Physical activity was assessed by steps accumulated during the school day, while MSC and PPC were assessed with the Test of Gross Motor Development--2nd edition (Ulrich, 2000) and the Pictorial Scale of Perceived Competence and Social Acceptance (Harter & Pike, 1984). Regression analyses revealed that preschool students' locomotor ability accounted for 21% (p = 0.007) of the variance associated with school-day physical activity. The findings support an association between participants' ability to locomote and be physically active. The findings warrant future investigations to examine the relationship between locomotor skills and physical activity behaviors. (Contains 3 tables.)