Abstract Objective Tinnitus distress can be reduced by means of cognitive–behavior therapy (CBT). To compensate for the shortage of CBT therapists, we aimed, in this study, to investigate the effects of a CBT-based self-help book guided by brief telephone support. Methods Seventy-two patients were randomized either to a self-help book and seven weekly phone calls or to a wait-list control condition, later on receiving the self-help book with less therapist support. The dropout rate was 7%. Follow-up data 1 year after completion of treatment were also collected (12% dropout). The Tinnitus Reaction Questionnaire (TRQ) was the main outcome measure, complemented with daily ratings of tinnitus and measures of insomnia, anxiety, and depression. Results On the TRQ, significant reductions were found in the treatment group both immediately following treatment and at 1-year follow-up. In the treatment group, 32% reached the criteria for clinical significance (at least 50% reduction of the TRQ) compared to 5% in the wait-list group. Directly after treatment, two out of five measures showed significant differences in favor of the treatment with more therapist support compared with the group who, after their waiting period, received little therapist support. The self-help treatment was estimated to be 2.6 (seven phone calls) and 4.8 (one phone call) times as cost-effective as regular CBT group treatment. Conclusions Guided self-help can serve as an alternative way to administer CBT for tinnitus. Preliminary results cast some doubts on the importance of weekly therapist contact. The effect size was somewhat smaller than for regular CBT, but on the other hand, the self-help seems far more cost-effective. Future studies should compare treatment modalities directly and explore cost-effectiveness more thoroughly.