OBJECTIVE: Treatments that alleviate insomnia over the long term are critical. We evaluated the relative long-term efficacy of cognitive therapy (CT), behavior therapy (BT), and cognitive behavior therapy (CBT) for insomnia. METHOD: Patients (N = 188, 62.2% female, 81.1% White, 6.5% Hispanic or Latinx, Mage = 47.4 years) with insomnia were randomized to eight sessions of CT, BT, or CBT for insomnia. Assessments at pretreatment and 12-month follow-up measured insomnia severity, insomnia response/remission, sleep diary parameters, and daytime functioning. RESULTS: Patients in all three treatment groups improved on insomnia severity, sleep onset latency, wake after sleep onset, total sleep time, sleep efficiency, work and social adjustment, and mental health (ps < .05). Moreover, in each treatment group, a substantial proportion of patients achieved remission and response. CBT was associated with larger improvements in insomnia severity relative to CT as well as greater remission and improvements in physical health, relative to CT and BT (ps < .05). For patients with a psychiatric comorbidity, CBT was associated with greater improvements in work and social adjustment and mental health, relative to CT (ps < 0.05). CT was not associated with change in time in bed, and none of the treatment conditions were associated with change in daytime fatigue (ps > .05). CONCLUSIONS: These encouraging results suggest that therapists may be able to offer CBT, BT, or CT to improve nighttime and daytime symptoms of insomnia over the long-term, with CBT offering a relative advantage for select outcomes and subgroups. (PsycInfo Database Record (c) 2023 APA, all rights reserved).