The system of supervising government primary schools in Pakistan is a matter of continuing debate. The performance of supervisors is frequently criticised, and their ability to improve the quality of education in primary schools is questioned. Periodically it is suggested that improvement requires a completely new supervisory cadre. The aim of this research is to clarify the purpose of primary school supervision, and to present evidence of both the practice of individual supervisors and their potential for achieving improvement in primary schools, in order to suggest ways in which the impact of supervision can be enhanced. Models of the supervisor as guardian, guide and innovator are distinguished and used to explain some of the conflicting demands made of supervisory personnel. The potential and limitations of work within each model are explored. Central to the research is a study which took place within the Sindh Primary Education Development Programme 1992-96, an internationally sponsored programme which included extensive training opportunities for supervisors. Questionnaire responses were collected during this training programme from ninety-one supervisors covering one rural and one urban district. Analysis focuses on the supervisors' perceptions of patterns of influence and achievement within their own work, using data from the questionnaires, interviews and seven individual life stories. The findings of this research challenge some influential assumptions about the centrality of primary teaching experience and specific training to ensure effective supervision. Instead,sincerity and respect emerge as key concepts of particular importance for sustaining professional endeavour. The results suggest that reforms of the selection and training of supervisory personnel are unlikely to influence practice permanently in Pakistan, unless accompanied by greater clarity about the precise role required, together with a revisioning of the relationships between the people within the education system as a whole founded on mutual respect for each others' work.