The publication of the Physical Education Curriculum (1999) in Ireland represented a significant step in providing quality opportunities for the development of the child through physical education. The focus of this thesis is on the potential impact of a programme of professional development in physical education on the provision of improved programmes of physical education for children in Irish primary schools. The programme of professional development based on the Physical Education Curriculum was developed and implemented for primary teachers who were assigned responsibility for leading in-service provision for physical education in the primary school. This programme was provided on a phased basis as they taught in their own school contexts and as they embarked as tutors on the facilitation o f the national in-service programme for primary teachers. Underlying the development of the programme are principles of adult learning, teacher change, professional development and programme design. The aims of the thesis are (1) to describe the development of a specific programme of professional development for tutors whose responsibility is to facilitate a programme of in-service education, (2) to evaluate its effectiveness in helping tutors to facilitate the programme, and (3) to investigate the views of a sample of teachers on the initial phase of the in-service programme and their intentions to implement the curriculum. Survey questionnaires, interviews and observations of tutors - as they taught physical education and as they facilitated the first phase of the in-service programme during the academic year 2004/2005 - were used to investigate the effectiveness of the programme of professional develoment. Similar methods were used to investigate the effect on teachers of the first phase of the in-service programme designed by the tutors. Findings from the study indicated that treatment of relevant content and use of a wide variety o f appropriate teaching methodologies significantly impacted on this programme of professional development. Issues such as the provision o f differentiated sessions, overload regarding treatment of content and the need for exploration of facilitation skills were highlighted. Data gathered revealed that engagement with the programme had impacted on many aspects of the teaching of physical education by tutors, particularly on their planning, the breadth of content taught and the range of methodologies used. In terms of preparing tutors to design and facilitate the in-service programme, the study found that tutors were satisfied that the programme had prepared them well for facilitation. This confidence to facilitate the in-service programme was based on factors such as their content and subject knowledge, the extended period they spent teaching physical education as they engaged with the programme o f professional development and time spent on planning for implementation of the in-service programme for teachers. Evidence gathered from tutors and from a small sample of teachers indicated an increased likelihood of teachers planning and implementing improved programmes of physical education provided constraints identified, such as those related to provision of further support for teachers and funding, are addressed. The study confirmed the importance of the development of expertise in physical education of primary teachers to build capacity to support the teaching o f physical education in Irish primary schools. The implementation of such a policy will require sustained support for the development of expertise beginning with quality programmes of professional development.