Entering residential treatment for an opioid use disorder (OUD) can elicit a stress response. Further, entering treatment diminishes the ability to use substances to cope. An inability to tolerate stressors while in residential treatment may impact treatment retention. Distress tolerance is described as the perceived ability to withstand stressors. The more distress tolerance someone has, the greater their ability to withstand stressors. This study uses clinical chart data from 197 individuals with heroin as their primary substance admitted to residential treatment in Baltimore, Maryland, USA, between October 2019 through February 2020. The purpose of this study is to examine the relationship between demographic characteristics, substance use characteristics, the distress tolerance scale, and treatment retention. Demographic characteristics, substance use characteristics, and the distress tolerance scale are captured during treatment admission. The treatment retention outcome is captured after an individual is discharged from treatment. Bivariate analyses will be conducted to examine the level of association between key variables. A linear regression model will be used to predict the length of stay in treatment. A logistic regression model will be used to predict treatment completion versus premature discharge. The primary predictor for these analyses is the total distress tolerance score. Findings from this study may provide insight into the relationship between distress tolerance and treatment retention.