Social service agencies increasingly report high rates of staff turnover, deficiencies in quality of services, and impeded implementation of evidenced-based treatments (EBT). Research suggests that these organizational challenges are largely attributed to inadequacies in supervision. Many supervisors identify insufficient training in competencies of managing supervisory relationships, employee performance, and supervisee professional development as the primary reason for addressing worker and agency needs. For over a decade, Hillside Family of Agencies (HFA) has encouraged its supervisors to be trained in Lawrence Shulman’s Interactional Supervision Approach (ISA) to develop the previously mentioned competencies. Considerable resources are dedicated toward having supervisors trained in ISA, yet it is unknown whether supervisors found the training effective. The purpose of this cross-sectional, quantitative study is to examine the effectiveness of ISA as perceived by HFA supervisory staff. The targeted sample consists of 352 HFA Supervisors recruited to take a self-administered, web-based survey. Univariate analysis are conducted to describe key variables involving ISA Training effectiveness, and bivariate analysis are used to compare differences in perceived effectiveness of training among supervisors. Based on previous research, it is anticipated that participants will report that ISA improved their ability to manage supervisory functions. It is projected that supervisors will identify additional training in ISA as beneficial toward their development. Understanding the perceived effectiveness of ISA is an essential first step toward determining HFA returns on its investment, and if warranted, concluding whether the agency is positioned in a manner that will further develop and ultimately sustain ISA.