Background Trans and gender diverse (TGD) youth often report poor relations with their parents and perceive these to be core to the mental health difficulties they experience. One aspect of psychological wellbeing that has not been well explored in relation to parental support is Quality of Life (QoL). Aim To test the association between perceived parental support and QoL and, understand from the young person’s perspective how parental support contributes to QoL. Method To address these aims a multi-methods design was used and 140 TGD youth aged 11–19 years old from the UK took part in an online survey in 2020. Validated measures of parental support and QoL were used in conjunction with open-ended survey questions about experiences of parental support. Findings As expected, we found a significant and positive association between parental support and QoL. Two themes were found in the qualitative data: (1) Parental support is not black or white, (2) Knowledge is a catalyst for affirmative parental support. Conclusions Our findings demonstrate the positive implications of affirmative family support on QoL but at the same time highlight how parental relations can be complex and frequently conditional. Organizations supporting young TGD people (e.g. those working in education, healthcare) should prepare young people for the complexity of family relationships. Knowledge and awareness were felt to be an important tool in increasing the likelihood of parental support, but affirmative and evidence-based support needs to be made more readily available.