ObjectiveText messaging has been proposed as a method for increasing the reach of interventions for harmful alcohol and other drug use. This paper describes the design of an automated text messaging adjunct to a substance use intervention intended to support adolescents and young adults attempting to change their alcohol and other drug use behavior. Feasibility and acceptability testing was conducted as part of this pilot study.MethodFive focus groups were conducted to refine text message content and finalize pilot intervention design. Automated, daily, substance use-related reminder text messages were sent to pilot intervention participants (n = 39), who were recruited from outpatient treatment.ResultsOf those who were invited, 63% enrolled in the study and 89.7% remained enrolled in the study as measured by completing at least one assessment after baseline. Participants reported a positive experience with the messages, particularly supportive/empowering messages and commitment reminder messages.ConclusionsThese findings suggest that text messaging is a feasible and acceptable method for delivery of substance use-related reminder content as an adjunct to substance use intervention.