Variations in mental health and sexual and reproductive health (SRH) outcomes of girls/women (cisgender and transgender) and gender-diverse (nonbinary, Two-Spirit, gender fluid, agender, queer, gender neutral) youth with intersectional identities exist and have largely been ignored in the literature. There is a lack of information on how these health services meet the health needs of girls/women and gender-diverse youth with intersectional identities and the quality of such services. The objective of this global realist review is to identify how, why, for whom, in what contexts and to what extent mental health and SRH services meet the health needs of girls/women (cisgender and transgender) and gender-diverse youth (10–25 years) with intersectional identities.

The protocol has been registered with PROSPERO and will follow Realist and Meta-narrative Evidence Syntheses Quality Standards for Realist Reviews. We will identify the programme theory and implementation determinants of mental health and SRH services for girls/women (cisgender and transgender) and gender-diverse (nonbinary, Two-Spirit, fluid, agender, queer, gender neutral) youth (10–25 years). The scope of the review will be defined in the first stage and will include consultations with youth Advisory Group members and initial programme theory development. An iterative search of scholarly bibliographic databases (MEDLINE, Embase, APA PsycInfo, CINAHL, Web of Science, IBSS) in addition to a grey literature search will take place in the second stage. The third stage will include evidence extraction and synthesis. In the final stage, the narrative will be developed and refined in consultation with Youth Advisory Group members, and findings will be disseminated.

The study was approved by the Research Ethics Board at the Centre for Addiction and Mental Health (2023/153). Findings will be disseminated through peer-reviewed publications, youth-friendly materials and webinars and national and international conferences.

CRD42024532422.