The U.S. Preventive Services Task Force (USPSTF) report on screening for Autism Spectrum Disorder (ASD) highlighted the need for research that examines the harms potentially associated with screening so as to assess the overall net benefit of universal screening. In response, this study engages qualitative, semi-structured interviews to generate a taxonomy outlining potential harms reported by parents and providers (pediatricians and Early Intervention providers) with experience in screening young children for ASD. Potential harms emerged including: physical, psychological, social, logistical/financial, opportunity cost, attrition, and exacerbation of non-targeted disparities. Respondents reported harms being experienced by the toddlers, parents, and providers. The harms reported highlight opportunities for providers to offer resources that mitigate the potential for these unintended consequences.