Background: Two goal perspectives predominate in achievement settings such as physical education (PE), namely task involvement, focused on self-referenced effort and improvement, and ego involvement, focused on normative ability comparisons. A task (mastery) involving motivational climate is associated with adaptive motivational responses, whereas an ego (performance) involving climate is associated with more maladaptive motivational outcomes. The task, authority, recognition, grouping, evaluation, and time (TARGET) structures of achievement situations have been found to influence motivational climate. It is possible to manipulate the TARGET structures in PE to create a mastery involving climate and enhance pupils' motivational responses. Purpose: The purpose of this study was to develop a mastery intervention programme for teacher education, based on self-observation of filmed PE lessons, and assess its effect on the TARGET teaching behaviours that influence motivational climate, pupils' perceptions of the motivational climate, and their cognitive and affective responses. Participants and setting: Four PE student teachers from the same UK university and a total of 80 (37 boys and 43 girls) pupils from two state comprehensive secondary schools in a large city in South Wales. Intervention: A six stage mastery intervention programme was designed based on self-evaluation of the TARGET structures from filmed PE lessons. Research design: Student teachers were each filmed teaching one pre- and one post-intervention lesson to the same class. Data collection: Teaching behaviours were assessed through an observational measure of TARGET behaviours. A questionnaire was administered to measure pupils' pre- and post-intervention perceptions of the motivational climate and cognitive and affective responses. Data analysis: Pre- and post-intervention mean percentage "mastery", "performance" and "neither" teaching behaviours were calculated for the TARGET behaviours. A series of repeated measures ANOVAs was conducted to determine whether any significant differences existed between pre- and post-intervention teaching behaviours. A repeated measures MANOVA was used in order to assess the effect of the intervention on pupils' perceptions of the motivational climate and their cognitive and affective responses. Secondary analysis involved a series of repeated measures ANOVAs for both high and low affect pupils on perceptions of the motivational climate and their cognitive and affective responses. Findings: The mastery intervention programme was successful in fostering more mastery involving teaching behaviours and higher perceptions of mastery involving TARGET behaviours. Contrary to the hypothesis, pupils' perceptions of a performance involving climate increased and there were no significant changes in their cognitive or affective responses. In accordance with the hypothesis, secondary analysis revealed that the more disaffected pupils significantly improved their motivational responses as a result of the intervention programme. Conclusions: A mastery intervention programme based on self-evaluation of teaching behaviours can increase mastery teaching behaviours and improve more disaffected pupils' motivation in PE. When given publicly to individual pupils, teacher feedback on effort and improvement may be perceived as performance rather than mastery involving. (Contains 6 tables.)