BACKGROUND: Critical reflection is vital for enhancing nursing competencies and patient care. This study aimed to validate and evaluate the psychometric properties of the Persian version of the critical reflection competency scale (CRCS-P) for clinical nurses. METHODS: This methodological study was conducted among clinical nurses in Ardabil, Iran, from July to September 2024. Participants included 201 nurses with at least six months of clinical experience. Psychometric properties were assessed following COSMIN guidelines, including content validity, construct validity through confirmatory factor analysis (CFA), and reliability testing. RESULTS: The CRCS-P demonstrated strong content validity, with Content Validity Index (CVI) scores ranging from 0.80 to 0.92. CFA results indicated robust construct validity, with fit indices showing CMIN/DF = 1.349, RMSEA = 0.034, GFI = 0.941, CFI = 0.989, NFI = 0.958, and AGFI = 0.921. Internal consistency was confirmed with a Cronbach's alpha of 0.862 and McDonald's omega coefficient of 0.871, and test-retest reliability yielded an Intraclass Correlation Coefficient (ICC) of 0.806. CONCLUSION: The CRCS-P is a valid and reliable tool for assessing critical reflection competencies among clinical nurses in Iran. This instrument can facilitate the integration of reflective practices into nursing education and professional development, ultimately enhancing patient care outcomes.