Relatively little is known about identity-related resilience factors associated with well-being among transgender and gender non-conforming (TGNC) people. Drawing upon theory on stigma-related stress and resilience and work examining group identification as a buffer against discrimination, the aim of the current study was to model perceived discrimination, transgender identification, and gender identity affirmation as predictors of well-being for TGNC people. We also tested whether the positive association between gender identity affirmation and well-being might be explained by the benefits affirmation has for individual self-concept clarity. Participants were 105 TGNC individuals (42% transgender male, 39% transgender female, 19% other gender non-conforming [e.g., non-binary]) recruited through online forums and support groups in the UK and North America who completed an online survey including self-report measures of key constructs. Results from structural equation models demonstrated that: (1) experiences of discrimination were associated with lower well-being overall, but having a stronger transgender identity moderated this association; (2) after adjustment for discrimination and transgender identification, experiences of gender identity affirmation were independently associated with greater well-being for TGNC people. Secondary analyses demonstrated that gender identity affirmation was linked to well-being through reinforcing a strong, internalized sense of clarity about individual self-concept. Results are discussed in terms of the implications for TGNC health and well-being, particularly with regard to the need for supportive, identity-affirming social environments.