Background The aim of this study was to complete the third phase of development of the Preceptor Self-Assessment Tool (PSAT). Method Psychometric testing was conducted via an online Qualtrics survey with a statewide sample of 320 nurse preceptors from July to September 2020. Exploratory factor analysis and internal consistency and scale reliability testing were conducted on the 64-item PSAT. Results Exploratory factor analysis identified three factors: (1) inter/intrapersonal skills and attitudes, (2) knowledge and understanding, and (3) administrative resources and support. Cronbach's alpha values for the PSAT-40 ranged from 0.978 to 0.998. Final scale reliability was excellent at 0.983. Conclusion The Preceptor Self-Assessment Tool, now in its final form as the PSAT-40, has established construct validity and reliability and can be used to assess competency as a preceptor. Nurse educators can use this instrument to assess the needs of nurse preceptors and develop strategic nursing preceptor education programs. [J Contin Educ Nurs. 2022;53(11):491-499.].