Background <p>Senior nursing students frequently encounter transition anxiety during internships, a phenomenon that adversely affects their mental health, academic performance, and the quality of patient care. Although Iran has introduced internship programs to reduce transition shock, their effectiveness remains unclear due to the lack of a validated Persian assessment tool. This study sought to evaluate the validity and reliability of the Persian adaptation of the school-to-work transition anxiety scale in nursing students.</p> Methods <p>This methodological research was carried out to examine the structural validity and internal reliability of the scale, utilizing data gathered from October 2024 to May 2025. A total population sampling approach was used. All eligible final-year nursing students were identified using the official enrollment list maintained by the faculty’s education office and were invited to participate. A total of 342 students participated and were divided into two independent samples: 171 participants for exploratory factor analysis (EFA) and 171 participants for confirmatory factor analysis (CFA). EFA, using the maximum likelihood extraction method with Promax rotation, was conducted to identify the latent factor structure. Subsequently, CFA was performed on the second independent sample to verify the proposed model. Convergent validity was assessed following the Fornell and Larcker approach by calculating the average variance extracted (AVE) and composite reliability (CR), while discriminant validity was evaluated using the Heterotrait-Monotrait (HTMT) ratio. Internal consistency was examined using Cronbach’s alpha and McDonald’s omega coefficients, and stability was assessed using the intraclass correlation coefficient (ICC).</p> Results <p>The study included 342 nursing students (55.85% male, mean age 22.81 ± 2.16 years, grade point average 16.83 ± 1.31). Qualitative face validity confirmed all items as clear, relevant, and important. Content validity was confirmed, with minor revisions to three items and the removal of five items (CVR &gt; 0.56). EFA extracted four factors (58.71% variance), with two items removed due to low factor loadings. CFA supported model fit (χ²/DF = 1.665, RMSEA = 0.063, CFI = 0.917). Convergent validity was confirmed for “Interpersonal Interactions” and “Fear of Being Infected” factors based on AVE and CR values. Discriminant validity was confirmed, as all HTMT coefficients were below the 0.85 threshold. Internal consistency of all factors was confirmed by Cronbach’s alpha and McDonald’s omega values greater than 0.7, and the stability of the scale was confirmed by evaluation of the ICC with 0.75 acceptable threshold. The final Persian version comprised 24 items across the same four-factor structure as the original 31-item scale.</p> Conclusion <p>The school-to-work transition anxiety scale demonstrated strong reliability and validity, confirming its suitability as a self-report instrument for assessing transition-related anxiety among final-year nursing students in Iran.</p>