The objectives of this study are to assess the magnitude and course of suicidal ideation during outpatient treatment and aftercare for adolescents with alcohol use disorders (AUD). One hundred seventy-seven adolescents meeting eligibility criteria, including no past 30-day suicidal behavior, participated in 9 weeks of outpatient cognitive-behavioral group therapy. Treatment completers were randomized into: (1) No-Active, (2) In-Person, or (3) Telephone aftercare conditions for a period of 12 weeks. No specific intervention for suicidal behavior was provided during the study. The Suicide Ideation Questionnaire (SIQ-JR, Reynolds, 1988) was administered at baseline, end of treatment, and end of aftercare. The results are as follows, a higher baseline suicidal ideation was associated with higher retention at the end of treatment and through aftercare. The In-Person Aftercare condition showed a significant decrease in suicidal ideation, relative to the No-Active Aftercare condition. There was a trend for similarly reduced severity of suicidal ideation in the Telephone Aftercare condition. In conclusion, the type of aftercare and resulting decrease in AUD may play a role in the reduction in suicidal ideation. The mechanism of change by which suicidal ideation is reduced in adolescents in treatment for AUD needs to be further explored.