BACKGROUND: People with tinnitus and/or hyperacusis often experience insomnia. However, it is unclear what factors are most strongly associated with insomnia. PURPOSE: To explore factors related to insomnia in patients with tinnitus and/or hyperacusis. RESEARCH DESIGN: This was a retrospective study using multiple-regression analysis. STUDY SAMPLE: Data were assessed for 444 consecutive patients who sought help concerning their tinnitus and/or hyperacusis from a specialist audiology center in the UK National Health Service. The average age of the patients was 54 years (standard deviation = 15 years). DATA COLLECTION AND ANALYSIS: The results of audiological tests and self-report questionnaires were gathered retrospectively from the records of the patients. Multiple-regression analysis was used to assess the relationship between insomnia and other variables. RESULTS: Sixty-nine percent of patients with tinnitus experienced some form of insomnia as measured via the Insomnia Severity Index (ISI). A multiple-regression model showed that ISI scores were significantly associated with depression scores measured via the depression subscale of the Hospital Anxiety and Depression Scale (HADS) (regression coefficient [b] = 0.44, p < 0.001), tinnitus annoyance measured via the visual analog scale (VAS) (b = 0.49, p = 0.001), anxiety measured via the anxiety subscale of the HADS (b = 0.21, p = 0.012), and tinnitus handicap measured via the Tinnitus Handicap Inventory (b = 0.07, p < 0.001). The model explained 45% of the variance in ISI scores. VAS scores for tinnitus loudness, hyperacusis-related measures, hearing thresholds, age, and gender were not significantly related to insomnia. CONCLUSIONS: The prevalence of insomnia in patients with tinnitus is high. Both tinnitus-related factors and psychological factors are related to the severity of insomnia. Hyperacusis is not significantly associated with insomnia.