The purpose of this study was to develop and validate the School-Based Counseling Self-Efficacy Scale (SB-SES). Two hundred sixty-five (N = 265) licensed mental health professionals participated in this study. Fifty-eight percent of the participants reported experience working as a school-based counselor with the remaining 42% reporting no school-based counseling experience. The participants were asked to complete the SB-SES, the Rosenberg Self-Esteem Scale (RSES; Rosenberg, 1989), the Counseling Self-Estimate Inventory (COSE; Larson et al., 1992), and a demographic sheet. The participants at one mental health agency were provided paper versions of the surveys and three weeks later completed the SB-SES again in order to assess for the stability of the SB-SES over time. Results of testing the psychometric properties of the SB-SES were positive. Reliability estimates suggested that the SB-SES is internally consistent. Though the results of testing the test-retest reliability of the SB-SES were promising, the results should be interpreted cautiously due to the low number of usable surveys for this analysis. Item validity of the SB-SES was supported through expert judges' ratings of the items. Convergent and discriminant validity of the SB-SES were also supported by comparing scores on the SB-SES with scores on the COSE (Larson et al., 1992) and the RSES (Rosenberg, 1989). The results related to the five-factor solution factor analysis of the SB-SES, though promising, did not support construct validity. After further exploration of these results, post hoc analyses with a four-factor solution factor analysis were conducted. The results of these post hoc analyses resulted in stronger support for the construct validity of the SB-SES. The results of this study suggest that the SB-SES shows promise for assessing school-based counseling self-efficacy. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]