The current significantly high prevalence rates of autism spectrum disorder (ASD) coupled with the paradigm shift from exclusive to inclusive education warrants research on inclusion of children with ASD in mainstream classrooms in Zimbabwe. A qualitative methodology was used to interview 21 regular primary school teachers regarding social barriers and enablers of inclusion of 6-12 year old children with ASD in mainstream classrooms in Harare educational province of Zimbabwe. Data analysis comprised pattern coding and cross-case analysis. Social rejection, communication impairments and behavioural challenges of children with ASD interfered with inclusion in mainstream classrooms. Regular teachers' training, stakeholder collaboration and institutionalization of social support services and programmes would facilitate the inclusion of children with ASD in mainstream classrooms.