Students with autism display sensory sensitivities to environmental stimuli that affect their attending and engagement in classroom learning activities. The purpose of the study was to determine whether attending of 4 male students, ages 13–20, increased after the installation of sound-absorbing walls and halogen lighting. The multiple single-subject, mixed-method design, AB(B+C), included a 2-wk baseline and two intervention phases: 2 wk after sound-absorbing wall installation using the Owens Corning Basement Finishing System™ (Owens Corning, Toledo, OH) and 2 wk after halogen light installation. We calculated nonattending frequencies from videotaped class sessions and used visual analysis to measure within-phase and between-phase characteristics. Results included increased frequency and stability of attending and engagement and improved classroom performance, comfort, and mood. Journaling provided students’ perspective on the modifications and reflected overall increased sensory comfort and themes of improved classroom environment, positive emotional response (mood), and improved classroom performance.