Objectives Internationally, children's movement competence levels are low. This study's aim was to evaluate the effectiveness of a 16 week gymnastics curriculum on stability, locomotive and object control skills and general body coordination. It was hypothesised that the gymnastics intervention group would demonstrate significant improvements beyond a PE comparison group. Design This study used a non-randomised control design. The intervention and comparison groups were drawn from three primary schools. The study followed the transparent reporting of evaluations with nonrandomized designs (TREND) statement for reporting. Methods A total of 333 children (51% girls, 41% intervention) with a mean age of 8.1 years (SD = 1.1) participated. Intervention children (16 weeks × 2 h of gymnastics) were compared to children who received (16 × 2 h) standard PE curriculum. Children's movement competence was assessed using the Test of Gross Motor Development-2, Stability Skills Assessment and the Körper-Koordinationstest für Kinder. Multilevel linear mixed models, accounting for variation at the class level and adjusted for age and sex, were used to assess intervention relative to comparison differences in all aspects of movement competence. Results Stability and object control skills showed a significant (p < 0.05) intervention × time interaction effect. No difference was found in locomotor skills or general coordination. Conclusions Gymnastics is effective at developing stability skills and object control skills without hindering the development of locomotor skills or general coordination. Accelerated learning of stability skills may support the development of more complex movement skills.