Systems Training for Emotional Predictability and Problem Solving (STEPPS) is an evidence-based group treatment program for ambulatory patients with borderline personality disorder (BPD). The program was introduced to the Iowa correctional system in 2005, and groups have been ongoing ever since. In this analysis, we examine whether response to the STEPPS program differs based on sex, age (<40/≥40 years), or race/ethnicity (minority/non-minority) using data collected in Iowa prisons and in community corrections. Subjects were recruited and assessed by correctional staff. Offenders with BPD were offered the opportunity to participate in the STEPPS program. The presence of BPD was assessed using a module from the Structured Interview for DSM-IV Personality. Efficacy assessments included the Borderline Evaluation of Severity Over Time Scale, the Beck Depression Inventory, and the Positive and Negative Affectivity Scale. The Client Satisfaction Questionnaire-8 assessed program satisfaction. Data on 77 offenders were analyzed. All participated in the STEPPS program and 53% completed all 20 weeks. The analysis showed that there were no significant differences in response to STEPPS in terms of sex, age, or race/ethnicity on any of the three efficacy measures. Women expressed greater satisfaction than men, but there were no differences with regard to age or race/ethnicity. The implications of the findings are discussed.