Objectives: Life review therapy is recognized as an evidence-based treatment for depression in later life. The current article evaluates an online life review therapy in middle-aged and older persons, comparing a counselor-led to a peer-supported mode of delivery. Methods: A pilot randomized controlled trial (RCT) was carried out with 3 conditions and 4 measurement points: (a) online life review therapy with online counseling, (b) online life review therapy with online peer support, and (c) a waitlist control condition. A mixed methods study provided insight in the reach, adherence, effectiveness, user experiences, and acceptability. Results: Fifty-eight people were included in the study. The intervention reached a vulnerable group of mainly middle-aged, college-educated women. The pilot RCT on effectiveness showed that participants in all conditions improved significantly in depressive symptoms, engaged living, mastery, and vitality, but not in ego integrity and despair, social support, loneliness, and well-being. The adherence, user experience, and acceptability were better in the counselor condition than in the peer condition. No differences were found between middle-aged and older adults. Conclusion: Despite the nonsignificant effects, possibly due to the small sample size, online life review therapy might be a good method for alleviating depressive symptoms in people in their second half of life. Further research is needed, addressing how online life review is best offered.