The Participation and Sensory Environment Questionnaire-Teacher Version (PSEQ-TV) is a teacher-report questionnaire to assess the impact of the sensory environment on participation of preschool children with autism spectrum disorder (ASD). Many children with ASD have sensory processing differences, although these differences are frequently examined from the standpoint of the person. The PSEQ-TV provides a single assessment to examine both participation and the sensory environment for preschool aged children with ASD. This study established the reliability of the PSEQ-TV including internal consistency of 0.98 and test-rest reliability of 0.70. The results indicate initial reliability of PSEQ-TV as an instrument that can be used to identify sensory environmental barriers within the preschool setting to target during interventions to increase participation.