[en] Motivational aspects play a particularly important role in teaching. They are considered a powerful mediator between teacher action and teaching effects. Pupils’ motivation towards school and physical education has already been analysed from the pupils’ point of view (Piéron, Ledent, Almond, Airstone and Newsburry, 1996). On another side, its perception by teachers is less documented. This study focused on the identification by PE teachers of pupils’ behaviours indicating that they were motivated or not. Moreover, perception of reasons related to lack of motivation in pupils was also investigated. Twenty-nine teachers fulfilled a questionnaire during an inservice preparation seminar. Their answers were analysed and inductively classified in categories. Thirteen categories of criteria showing the presence or lack of motivation were identified. Motivation was predominantly perceived by (1) the quality of the working climate (16.8%); (2) the intend to be involved in the PE lesson (14%); (3) positive reactions towards the subject matter (11.2%) and an efficient time management (11.2%). The most important categories related to lack of motivation were: (1) absences or excuses (20.2%); (2) low time on task (14%) and (3) negative reactions towards the subject matter (14%). Concerning origins of the lack of motivation, teachers emphasised: (1) the large differences between pupils (13.7%); the lack of sport culture of youth (10.5%) and (3) the negative pupils’ attitude towards school.