This review synthesizes evidence on the effectiveness of the World Athletics Kids’ Athletics Programme in improving motor competence, physical fitness and psychosocial outcomes among school-aged children (typically aged 6–12 years). The results indicate consistent positive effects of the programme on running speed, agility and object control skills compared to standard physical education or no intervention, with small-to-medium effect sizes. Evidence for improvements in cardiorespiratory fitness and upper-body strength was less robust, with mixed findings. Psychosocially, the programme demonstrated moderate improvements in enjoyment of physical activity and perceived athletic competence, but no significant effects on long-term behavioural outcomes such as sustained participation. Heterogeneity in intervention duration (4–24 weeks), delivery agents (teachers vs. coaches), and outcome measures limited the comparability of some findings. Overall, the World Athletics Kids’ Athletics Programme appears effective for enhancing selected motor and physical fitness components and fostering positive attitudes towards running-based activities in the short term, though longer-term and psychosocial impacts remain less certain. High-quality, cluster-randomized trials with follow-up assessments are needed to strengthen the evidence base.