<p>There is growing interest in the experiences of transgender and gender diverse (TGD) people and those who discontinue or reverse their gender transition, known as detransition. While an understanding of their similarities and differences could inform better psychological support, no study has simultaneously recruited and compared both groups. In this study, we describe and compare two groups of 29 TGD (<i>M</i>_<i>age</i> = 28.28, 72.4% assigned female at birth) and 22 detransitioning participants (<i>M</i>_<i>age</i> = 28.73, 63.6% assigned female at birth). The criterion for categorizing the detransition group was stopping, shifting, or reversing gender transition alongside a change in gender self-conceptualization. Participants completed two short online surveys and took part in two face-to-face assessments covering their transition/detransition history, including the steps taken during the process, and self-reported mental health, including diagnoses, psychopharmacological medication, and adverse life experiences. All reported social transition, 74.5% administrative transition, and 84.3% medical transition. Detransitioning participants started medical transition at a significantly younger age. In addition, there was a higher proportion of detransitioning participants who reported side/unwanted effects of gender-affirming hormonal treatment, and of TGD participants with interest in further medical interventions. No significant differences were found for other variables. A high percentage of participants in both groups self-disclosed a history of poor mental health and adverse life experiences. The findings highlight the diversity of trajectories following gender transition, the difficulty of predicting them, and their importance for informing future mental health services and support.</p>