Children who are proficient in a broad range of FMS, which include locomotor (e.g. run, jump, hop), object-control (e.g. throw, catch, kick) and balance skills, are more likely to have the confidence and motivation to regularly engage in physical activity and sport. Initial results of this research revealed that among a sample of 414 primary school children, between 2% and 38% achieved mastery across 15 different FMS. In addition, females displayed significantly poorer object-control skill proficiency than males, whilst overweight/obese children were significantly poorer in both locomotor and object-control skills compared to non-overweight children. Subsequently, a school based intervention programme was designed and delivered that aimed to support FMS development for all children regardless of sex or weight status. Findings suggest that lessons delivered by an instructor with specialist FMS knowledge and which emphasise self-improvement rather than competition and winning can enhance FMS proficiency levels, and is beneficial for all children, including females and overweight children. As primary school teachers are responsible for teaching PE to all children attending primary school, they are ideally situated to support children’s FMS development. However, many teachers have received limited training in teaching PE and may not have the confidence to deliver high quality PE lessons. Consequently, the final phase of this research involved the design, delivery and evaluation of a comprehensive questionnaire to understand teachers perceptions, attitudes and perceived confidence to teach PE in Irish primary schools. In brief, results revealed that despite having positive attitudes towards teaching PE, primary school teachers in Ireland do not feel confident to teach all aspects of the PE curriculum equally. Male teachers had better attitudes and overall, felt more confident to teach PE compared to female teachers. Results also revealed that FMS-based in-service training may enhance teacher confidence to teach PE lessons to a greater extent than non-FMS based in-service training.