This study addresses the development of a teacher questionnaire to assess the social participation of pupils with special needs in regular primary schools and is divided into 2 parts. In the 1st part, the construction of the questionnaire is described. The questionnaire consists of 30 statements related to 4 key themes of social participation: "friendships/relationships", "contacts/interactions", "perception of the pupil", and "acceptance by classmates", yielding 4 subscales. The 2nd part of the study addresses an empirical study in which the questionnaire's quality was examined. The outcomes of a confirmatory factor analysis largely supported the division of social participation into 4 key themes. The analysis revealed that 22 out of 30 statements correlated strongest with the subscale they were assigned to. The questionnaire as a whole turned out to be reliable, whereas the reliability of the subscales varied. The construct validity was found to be mainly acceptable. (Contains 1 figure and 3 tables.)