Increasing numbers of CYP across the UK are identifying and expressing themselves in ways that do not correspond with their sex assigned at birth. Nevertheless, they are frequently reported to be among the most oppressed and marginalised within school cultures, with research highlighting adverse experiences and poorer outcomes associated with gender diverse populations. Educational Psychologists (EPs) are well placed to improve outcomes for gender diverse young people yet currently there is no professional body guidance to support this work. This absence creates a need to explore current experience and practice, both in the UK and globally, and to consider how to support practitioners moving forwards. A systematic literature review was conducted to explore the experiences and perspectives of school-based psychological professionals supporting gender diverse CYP across the world. A thematic synthesis was conducted with eighteen studies that met the inclusion criteria. Four analytic themes were created from this; ‘The environment I work in is key’, ‘how do I know what to do?’, ‘advocacy is central to my work’, ‘I am fighting against barriers and systems’. Strengths and limitations were discussed, alongside implications for practice. The empirical project explored current EP and TEP practice with gender diverse CYP. A survey was sent to EPs and TEPs across the UK in which they were presented with a scenario and asked how they might respond, what informed their thinking and decision making, and what they felt would support their practice moving forwards, including what guidance should include. Medium q ‘codebook’ thematic analysis was used to analyse the responses of 75 EP and TEPs to the vignette, with responses relevant to each research question analysed separately. Strengths and limitations were considered and implications for policy and practice within the UK were discussed.