This study aimed to fulfill a twofold purpose. First, a 12-session reality therapy drug treatment program to enhance substance-involved females’ self-efficacy in three aspects, which have been demonstrated to be essential to recovery, was designed and implemented. Second, to test the effectiveness of the treatment program, the Index of Sense of Self-Efficacy Scale was developed and validated using Principal Component Analysis and Confirmatory Factor Analysis. The participants in the drug treatment program were 40 incarcerated substance-involved female offenders, who were randomly assigned to equal-sized experimental and control groups. The results of the study, obtained by ANCOVA analysis, showed significant differences in the post-test scores for sense of self-efficacy in decision making, action-planning, and coping and social skills for the members of the two groups.