An analysis of teaching using a social skill model, and a review of the research on nonverbal behaviour, led to the hypothesis that awareness of nonverbal behaviour is an important feature of the teaching process. Two aspects of awareness were identified: the teacher's awareness of his or her own nonverbal actions and the teacher's awareness of the pupils' nonverbal messages. An inventory was used to assess student teachers' perception of themselves and significant relationships were found between scores on the inventory and supervisors' judgements of the students' teaching competence. Another assessment which compares student statements of their nonverbal activity in classrooms with tutors' observations of that activity also revealed significant relationships with teaching competence. The relationships for samples of students who taught in junior schools differed from those for students in secondary schools. These differences are explained in terms of differing styles, demands and expectations in the two types of school. The teachers' awareness of the pupils' nonverbal signals was assessed by a specially constructed video-test of those signals. Scores on this test related significantly with teaching competence ratings. The assessment of self-awareness has little relationship to the assessment of awareness of pupils; it is concluded that the two skills are separate. When the measure of awareness of oneself was considered in association with the awareness of the pupils it was found that students scoring low on both measures tended to be of lower teaching competence. Higher teaching competence, however, was related to the association of high self-awareness with low awareness of pupils. An explanation in terms of perceptual overload and of limited processing capacity is offered. In conclusion the original social skills model is modified to include these results and suggestions offered as to the implications for teacher training. These suggestions include a note of the nonverbal cues used by student teachers when making inferences about pupils.