Background: Previous studies have evaluated the competency of newly graduated nurses and nurses. However, most of the instruments used include a large number of items that make completing them a time-consuming process. A brief instrument may be more acceptable and feasible for use in these evaluations.Purpose: This study was designed to develop the brief capstone core competency (CCC or 3C) scale and validate its effectiveness in evaluating the academic and practical performance of nursing students enrolled in a bachelor's degree program.Methods: A cross-sectional study was conducted. The 3C scale was developed in two phases. In Phase I, the items were summed from literature reviews, an expert panel, known-groups validity, test-retest reliability, internal consistency reliability, and exploratory factor analysis. In Phase II, the efficacy of the instrument was confirmed using confirmative factor analysis. Five hundred ninety-six participants participated in the first phase, and 520 participants participated in the second phase. The study period was 2016-2017.Results: The 3C scale includes 24 items distinguished into a three-component structure that accounts for 67.85% of the total variance. The three components include nursing intelligence, nursing humanity, and nursing career. The 3C scale was found to have high levels of internal consistency reliability (.97) and test-retest stability reliability (r = .97). A significant statistical difference in the performance level was examined between senior and junior nursing students. The hypothesized three-factor model fit index showed w 2 /df = 1338.25/249, p < .001, goodness-of-fit index = .82, comparative fit index = .90, root mean square error of approximation = .09, and standardized root mean square residual = .06. The participants were found to have excellent nursing humanity competency. Conclusions:The developed 3C scale exhibited satisfactory reliability and validity for use with nursing students. The 3C scale may be used to evaluate the performance of nursing students during their learning process, and the results may be used to evaluate changes in educational outcomes.