Purpose: To improve the quality of postoperative care and promote recovery after surgery, it is important that nursing education is competency-based and that competency assessment is an integral part of the educational process. The purpose of this study was to develop a tool to evaluate nursing students’ perceived competence in postoperative care. Methods: This cross-sectional methodological study followed DeVellis’s scale development steps and was conducted between December 2022 and March 2023. In this study, 892 students were invited and 703 responded. After exclusions, data from 645 students were analyzed to examine the psychometric structure of the scale using exploratory factor analysis (n=327) and confirmatory factor analysis (n=318). Reliability was assessed by calculating Cronbach’s α coefficients and by test–retest measurement (n=46). Results: The proposed scale was confirmed to consist of five factors and 28 items (χ2/degrees of freedom=2.25, root mean square error of approximation=.06, normed fit index=.90, and goodness-of-fit index=.85). Cronbach’s α was .97 for the total scale. The data demonstrated high test–retest stability (intraclass correlation coefficient=.88). The scale developed and psychometrically tested in this study revealed a five-factor structure: legal responsibilities and ethical principles (seven items), postoperative nursing care (seven items), interpersonal relations and communication (four items), leadership (six items), and education and professional development (four items). Conclusion The scale, which demonstrated very good psychometric properties, would be helpful in assessing perceived postoperative nursing competence among nursing students. This may help students graduate with the necessary knowledge and skills required for postoperative care. However, further research involving larger samples and more diverse cultural contexts is needed to enhance the generalizability of the scale.