Background: Patient adherence has been identified as an important barrier to the implementation of evidence-based psychological treatments. Objective: In cognitive behavioral treatments (CBT) for insomnia, the current study examined (a) the validity of therapist ratings of patient agreement and adherence against an established behavioral measure of adherence, and (b) the relationship between treatment agreement, adherence, and outcome. Method: Participants were 188 adults meeting DSM–IV–TR criteria for chronic insomnia who were randomized to receive behavior therapy, cognitive therapy, or CBT for insomnia. Treatment agreement/adherence was measured by (a) weekly therapist ratings of patient agreement and homework completion, and (b) adherence to behavioral strategies (ABS) derived from patient-reported sleep diary. Outcome measures were Insomnia Severity Index and insomnia remission (Insomnia Severity Index <8). Results: Therapist ratings of patient agreement as well as homework completion were significantly associated with sleep diary-derived global ABS. Therapist-rated patient agreement and homework completion as well as global ABS predicted greater insomnia symptoms reduction from pretreatment to posttreatment. Patient agreement also predicted insomnia symptoms reduction from pretreatment to 6-month follow-up. Patient agreement, adherence, and ABS measures during treatment significantly predicted insomnia remission at posttreatment, and all but therapist rating of homework completion predicted remission at 6-month follow-up. Conclusions: Greater patient agreement and adherence (therapist ratings and ABS) during treatment predicted better treatment outcome. Therapist-rated treatment agreement and adherence correspond well with patient-reported sleep diary-derived adherence measure. These simple, deployable therapist-rated patient agreement and adherence can potentially be useful for treatments for other disorders.