Purpose <p>First signs of autism are typically noticed in a child’s early development. When parents or carers first become aware of developmental differences in their child, they are likely to experience feelings of concern and uncertainty and may seek advice from healthcare professionals (HCPs). This consultation is a pivotal encounter with respect to how supported parents feel, and whether or not they pursue an autism assessment for their child. While previous reviews have focused broadly on parents’ experiences of and journey to autism assessments for their children, no review has focused specifically on parents’ first experiences with HCPs.</p> Methods <p>Using reflexive thematic analysis, this qualitative systematic review synthesised findings from twenty-five studies, with the aim of exploring parents of autistic children’s first experiences with HCPs when they had concerns in relation to their child’s development, and the perceived impact of that first encounter.</p> Results <p>Three key themes were identified which included: parents’ first encounters with HCPs, which were mostly described as unhelpful; autism awareness and knowledge amongst healthcare professionals as perceived by parents; and the impact of racial, ethnic, and gender biases on this first encounter.</p> Conclusion <p>Findings highlight the importance of HCPs being receptive to parental concerns, especially during first encounters with parents. The importance of autism specific training for healthcare professional, with specific focus on clarifying autism assessment pathways and communicating the heterogenous nature of autism was also highlighted.</p>