The presence of a child with Autism Spectrum Disorder (ASD) in the family can have a negative impact on parental Quality of Life (QoL), but evidence on how treatments for children with ASD can affect parental QoL is currently limited. In this qualitative study, we develop a semi-structured interview in order to investigate the impact of ASD on the QoL of mothers and fathers from a subjective perspective, as well as the effect of the intervention on their QoL and adjustment process. The sample consisted of 31 parents of children with ASD severity 2 or 3, aged 5 to 11 years, undergoing a multidisciplinary intervention. In order to identify emerging themes from the interview transcripts, a Thematic Analysis was conducted using a bottom-up approach. We identified three main themes relating to parental QoL (ASD impact on QoL, useful external resources, QoL improvement-related factors) and five themes relating to parents' views on the intervention (positive impact on parent, dissatisfaction with previous interventions, parental involvement, useful features, critical issues). The results provide indications of the process of parental adaptation and the components of interventions that foster an improvement in their QoL. In conclusion, living with a child with ASD can have a significant influence on a parents' QoL, not just physically and emotionally, but also in terms of general goals, family structure, and social interactions.