Objectives <p>Research has demonstrated the importance and utility of soft skills within behavior analysis. Previous research has indicated that when therapists engage in appropriate soft skills, such as relationship or rapport building, individuals show increased indices of happiness and compliance, as well as reduced problem behavior. Despite relevant research on teaching soft skills and related conceptual discussion on the importance of soft skills, limited empirical evaluations have been conducted which have objectively evaluated the direct effect soft skills may have on client behavior. The objective of this study was to evaluate the relative effect of the soft skill of kindness on client behavior when embedded within therapy sessions.</p> Methods <p>This study employed an alternating treatments design that was replicated across three participants who were exposed to both kind and neutral conditions. The primary dependent variables were skill acquisition, problem behavior occurrence, on-task behavior, and indices of happiness or unhappiness. Additionally, after exposure to the treatment conditions, participants were provided the choice of selecting which condition they preferred.</p> Results <p>The findings indicated that individuals preferred the kind treatment condition and showed decreased problem behavior, increased skill acquisition, increased on-task behavior, and increased levels of happiness and decreased levels of unhappiness when exposed to this condition as well.</p> Conclusions <p>Kindness as defined within the study may result in positive improvements in behavior and higher levels of happiness with clients when embedded within therapy sessions. Additional research is needed to further evaluate the impact of kindness and other soft skills within therapy sessions.</p>