Understanding gender identity in transgender and gender-diverse (TGD) individuals is crucial for effective care. The Gender Preoccupation and Stability Questionnaire (GPSQ) measures the preoccupation and stability of gender identity, but no Italian validation is available.

This study aimed to translate, culturally adapt and validate the Italian version of the GPSQ in a clinical sample of TGD adults.

The GPSQ was translated with a forward–backward method and completed by 151 TGD adults at a gender clinic. Participants also filled out the Symptom Checklist-58 and Body Uneasiness Test. We assessed structural validity (EFA), internal consistency, test–retest reliability, and examined known-groups and predictive validity.

The EFA supported a four-factor structure – Gender Identity Instability, Cognitive-Affective Salience, Preoccupation, and Distress/Intervention-Oriented Reflection – with good fit (root mean square error of approximation 0.06; Comparative Fit Index 0.95; Tucker–Lewis Index 0.93; standard root mean square residual 0.04). The GPSQ showed solid internal consistency (α = 0.78; ω = 0.73) and excellent test–retest reliability (r = 0.98; intraclass correlation coefficient 0.98). Higher scores correlated with psychological distress (r = 0.55, p < 0.001) and body image concerns (r = 0.48, p < 0.001). Preoccupation was most linked to obsessive–compulsive symptoms, and Cognitive-Affective Salience to body image concerns. Participants not on hormones scored higher (p = 0.010, Cohen’s d = 0.36).

The Italian GPSQ is a reliable and valid tool to assess gender-related preoccupation and identity instability in TGD individuals. Its multidimensional structure makes it useful in both clinical practice and research in the Italian context.