Gender affirming healthcare refers to a range of treatments and procedures which aim to alleviate gender dysphoria in transgender patients by bringing their bodies into alignment with their gender identities. These treatments can include gender affirming hormone therapy (GAHT) and various surgeries. This research, which was influenced by PPI (patient and public involvement) , aimed to explore the factors associated with experiences of gender affirming healthcare through two studies: (i) a systematic review of factors associated with gender affirming healthcare in existing literature, and (ii) a qualitative study consisting of interviews with ten transgender people (four males, four females, two non-binary) living in Ireland which explored expectations and experiences of gender affirming healthcare. The findings of these two studies suggest that a range of factors are associated with experiences. The systematic review included 38 studies from 13 different countries and found that factors associated with experiences broadly fell into the categories of sociodemographic factors, treatment-related factors, and psychosocial factors, such as interactions with healthcare professionals (HCPs). The qualitative study found that experiences of transgender people seeking treatment in Ireland were mixed, with positive experiences generally relating to treatments themselves and negative experiences generally relating to interactions with HCPs and barriers to care. Common barriers included waiting times, cost, and distance to gender clinics. Social support was frequently reported as an important factor in seeking care. Participants often sought information online and from other transgender people due to a lack of available information and lack of knowledge among HCPs. Information from these sources often shaped participant expectations which in turn shaped experiences. A list of recommendations for those involved in supporting patients undergoing gender affirming healthcare has been developed based on the findings of these studies. This suggests a number of ways in which transgender patients could be better supported through the transition process.