Reflexivity - the extent to which teams reflect upon and modify their functioning - has been identified as a possible key factor in the effectiveness of work teams. The aim of the present study was to develop a questionnaire to measure (aspects of) reflexivity, with a focus on team reflection. The questionnaire was tested in two different samples, namely a first sample of 59 teams from 14 different organisations (Study 1) and a confirmation sample of 59 school management teams (Study 2). In both samples, two factors of reflection were identified. These were labeled evaluation/learning and discussing processes. Scale statistics showed good psychometric properties for the scales in both studies. We conclude that the scales form a parsimonious and valid instrument to assess reflexivity in teams.