Objective: Clinicians' perceptions of CBT-I Coach, a patient-facing mobile app for cognitive-behavioral therapy for insomnia (CBT-I), are critical to its adoption and integration into practice. Diffusion of innovations theory emphasizes the influence of perceptions, including the relative advantage to current practice, the compatibility to clinicians' needs, the complexity, the innovation's trialability, and observability. This study intended to evaluate the use and perceptions of CBT-I Coach among Veterans Affairs (VA)-trained CBT-I clinicians. Participants and Methods: Clinicians (N = 108) were surveyed about their use, feedback, and perceptions of CBT-I Coach a year after the app became available. Results: Overall perceptions of CBT-I Coach were favorable. Fifty percent of clinicians reported using CBT-I Coach, with 98% intending to continue use. The app was perceived to increase sleep diary completion and homework compliance. Clinicians viewed the app as providing accessibility to helpful tools and improving patient engagement. Of those not using the app, 83% endorsed intention to use it. Reasons for nonuse were lack of patient access to smart phones, not being aware of the app, not having time to learn it, and inability to directly access app data. Those who reported using CBT-I Coach had more favorable perceptions across all constructs (p < .01 - p < .001), except relative advantage, compared to nonusers. Users perceived it as less complex and more compatible with their practice than nonusers. Conclusions: Continued efforts are needed to increase adoption and enhance use of CBT-I Coach, as well as study if reported benefits can be evidenced more directly.