<p>Emerging research suggests that transnormativity plays an important role in the lives and mental health of transgender and/or nonbinary (TNB) people. Transnormativity encompasses the norms and standards by which the legitimacy of TNB peoples’ gender identities and expressions are measured. This study examined the mediating and moderating role of internalized transnormativity in the association between two forms of gender dysphoria (physical and social) and psychological distress. A sample of TNB adults between the ages of 18 and 65 (<i>N</i> = 472; 202 trans women, 108 trans men, and 162 nonbinary individuals) completed an online survey. Mediation and moderation analyses were then conducted to explore the role of internalized transnormativity within the association between: (1) physical gender dysphoria and psychological distress and (2) social gender dysphoria and psychological distress. Internalized transnormativity partially mediated, but did not moderate, the association between physical or social gender dysphoria and psychological distress. For physical gender dysphoria, this mediation followed a typical pattern, where higher levels of physical gender dysphoria predicted more psychological distress through higher internalized transnormativity. In contrast, the mediation involving social gender dysphoria reflected a suppression effect: higher social gender dysphoria was linked to lower internalized transnormativity, which itself was associated with greater psychological distress. This reduction in transnormativity functioned as a protective pathway, dampening the observed relationship between social gender dysphoria and psychological distress. As little quantitative literature on transnormativity exists, the results of this study provide novel insights into the influence transnormativity may exert on the mental health of TNB people.</p>