This study evaluated the classroom measure of active engagement (CMAE), an observational tool designed to measure active engagement in students with autism spectrum disorder (ASD). Participants included 196 students with ASD and their educators (n = 126) who were video-recorded at the beginning of the school year. Findings documented limited active engagement overall, with students spending less than half of the observation well-regulated, productive, or independent and infrequently directing eye gaze and communicating. Confirmatory factor analysis indicated that the structure of the CMAE was represented by a 5-factor model. These findings underscore the need for improved active engagement in students with ASD and show promise for a tool to measure behaviors associated with positive educational outcomes in students with ASD.