Young adults ages 18 to 25 have the highest percentage (5%) of cannabis use disorder (CUD) among all age groups, and are the least likely to receive treatment compared with other age groups. Because this population is in need of creative approaches for treatment engagement, we tested Peer Network Counseling-txt (PNC-txt), a 4-week, automated text-delivered cannabis treatment that focuses on close peer relations with 96 treatment seeking young adults. Participants meeting CUD criteria were randomized to PNC-txt, or assessment only control condition and followed for 3-months. At 3-months, the PNC-txt group reduced number of heavy cannabis-use days and relationship problems due to cannabis use compared with controls. Subgroup analyses were conducted with cases having more and fewer CUD symptoms than the full sample. For cases with fewer symptoms, but not for those with more, PNC-txt reduced past 30-day use, urges to use, memory problems, and relationship problems due to cannabis use compared with controls. Treatment satisfaction data from the full sample indicated that participants thought the intervention texts helped them reduce or manage their cannabis use and increased their understanding of the negative relational effects associated with ongoing cannabis use. Findings provide evidence of the efficacy of PNC-txt in treating CUD in young adults, support clinically targeting peer relations, and suggest that PNC-txt may be most helpful for those with mild to moderate CUD severity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).