Purpose: Children who do not learn their fundamental motor skills (FMS) are more likely to be unskilled, sedentary adults. By consequence, it behooves those teaching physical education to put in place mechanisms that promote as well as motivate children to master their FMS. One approach to achieving this goal is through the adoption of mastery motivational climates (MMC) in physical education. The purpose of this study was to determine the effects of a year-long (9-month) MMC physical education program on preschool children's FMS learning. Method: Participants (N = 96, MMC = 58, Comparison = 38) completed the Test of Gross Motor Development-Third Edition prior to and after intervention. Intact classrooms were randomly assigned to either a MMC or comparison group. A repeated measures nested MANOVA was used to test changes by group. Follow-up measurements included univariate repeated measures and simple effects analyses. Results: There were no significant multivariate differences based on class membership (p = 0.249), indicating the nested structure was not associated with any meaningful differences in test scores. There was a significant multivariate difference based on the interaction of time (pre- versus post-test) and group (p < 0.001). Both locomotor and ball skills significantly varied between groups and across time. Children in both groups improved from pre-test to post-test, but the rate of improvement was significantly greater for the MMC group. Conclusions: A year-long MMC intervention is beneficial for improving children's FMS.