ABSTRACT. Objective: Compared with older adults, emerging adults (18-29 years old) entering treatment typically have less severe alcohol use consequences. Also, their unique clinical presentations (e.g., modest initial abstinence motivation) and developmental contexts (e.g., drinkingrich social networks) may make a straightforward implementation of treatments developed for adults less effective. Yet, this has seldom been examined empirically. This study was a secondary analysis of Project MATCH (Matching Alcoholism Treatments to Client Heterogeneity) data examining (a) overall differences between emerging adults and older adults ( 30 years old) on outcomes during treatment and at 1-year follow-up, and (b) whether emerging adults had poorer outcomes on any of the three Project MATCH treatments in particular. Method: Participants were 267 emerging adults and 1,459 older adults randomly assigned to individually delivered cognitive-behavioral therapy (CBT), motivational enhancement therapy (MET), or 12-step facilitation (TSF).Multilevel growth curve models tested differences on percentage of days abstinent (PDA) and drinks per drinking day (DDD) by age group and treatment assignment. Results: During treatment, compared with older adults, emerging adults reported more DDD but similar PDA. Further, emerging adults assigned to TSF had less PDA and more DDD than emerging adults and older adults assigned to CBT or MET during treatment (i.e., emerging adults in TSF has poorer outcomes initially), but this matching effect was not evident at 1-year follow-up. Conclusions: This study is among the first to test age group differences across three psychosocial interventions shown to be efficacious treatments for alcohol use disorder. Although emerging adults generally did as well as their older counterparts, they may require a more developmentally sensitive approach to bolster TSF effects during treatment. (J.