The purpose of this study was to identify physical activity (PA) influences in children with autistic spectrum disorders (ASD), as perceived by parents and teachers. A number of developmental, environmental, sociocultural, and psychological factors have been reported to impact the PA behaviors of children (Sallis, Prochaska, & Taylor, 2000). However, the influence of impairment on already interactive and complex PA behavior may create the need to consider this population separately. Physical activity behaviors have not been specifically examined in children with an ASD, but these individuals may be at-risk for inactivity due to the characteristics of their condition. Children with an ASD demonstrate (a) restricted, repetitive, and stereotyped patterns of behavior, interests, and activities, (b) qualitative impairments in social interaction, and (c) qualitative impairments in communication (American Psychiatric Association, 2000), which may interfere with common modes of PA. Qualitative methodology is an appropriate method for exploring this issue because of its allowance for emerging themes from the participant perspective. Questions in existing survey instruments are typically based on data from other populations and preclude the identification of PA behaviors unique to children with an ASD. In addition, survey tools do not allow in-depth examination of the context of behaviors. To pursue this line of inquiry, Spradley’s (1979) ethnographic framework was used to develop interview questions. Fourteen parents and 14 teachers of children with an ASD agreed to participate in formal, tape recorded interviews consisting of open-ended questions relating to the PA of children with an ASD (n = 19). Parents documented child activity between 4:00 and 7:00 pm using a PA diary log, and children were systematically observed during recess and physical education. Data from interviews, conversational data, field notes, and diary logs were separated into critical incidents and analyzed using the constant comparison method of analysis. Emergent themes were reported using descriptive methods. Three salient factors affecting PA in this group emerged: impairment, environment, and sociocultural. Sub-themes emerging from impairment were social and communication deficits, transition issues, and inappropriate fear response. Sub-themes for environment included the shortage of accommodating community PA programs, untrained service providers, and technology. Sub-themes emerging from sociocultural were peer influence and parent-perceived barriers. Physical activity behaviors of children with and without an ASD resemble one another; however, children with an ASD also encounter unique factors that influence their PA behavior as a result of the specific characteristics of the disability. Keyword(s): adapted physical activity, physical activity, play