We propose a randomized, controlled trial of a video- and telephone-based, brief insomnia treatment in Veterans who meet criteria for Insomnia Disorder and Posttraumatic Stress Disorder (PTSD) to accomplish the goal of improving psychosocial functioning. The primary outcome for the trial will be psychosocial functioning, with insomnia severity serving as the secondary outcome. Additional goals include assessing durability of treatment gains and evaluating whether suicidal ideation decreases after insomnia treatment. Eighty Veterans with Insomnia Disorder and PTSD will be randomly assigned to either Brief Behavioral Treatment for Insomnia (BBTI; one 60-minute and one 30-minute video encounter, and two 20-minute phone- based encounters) or a Progressive Muscle Relaxation Training control group (manualized relaxation training delivered by two video and two phone sessions, matched to the BBTI condition for therapist time). Prior to randomization, participants will complete clinician-administered, mental health diagnostic interviews at baseline (and post-treatment). Self-report measures of psychosocial functioning, insomnia severity, and other mental health symptoms will be completed at baseline (pre-treatment), mid-treatment, post-treatment, and at 6-month follow-up (BBTI treatment group only). Sleep parameters will be completed with a self-report sleep diary. One week of sleep parameters data will be collected at baseline and continuously to the post-treatment appointment (and at 6-month follow-up for the BBTI treatment group only). We also will explore whether participation in BBTI helps to decrease suicidal ideation, which often occurs in Veterans with PTSD and insomnia. Information on suicidal ideation will be collected through the Depressive Symptom Index: Suicidality Subscale (DSI-SS) and the Columbia Suicide Severity Rating Scale (C-SSRS), the latter which is used clinically in the VA to assess suicide risk. We will allow Veterans with current suicidal ideation into the study but will exclude Veterans with current suicidal intent or a plan. Veterans who have suicidal ideation, but no intent or plan will be assessed at baseline, mid-treatment, and post- treatment and will be clinically monitored if any risk issues should emerge during treatment. This trial will provide useful information regarding rehabilitative outcomes, and it will yield specific information that will allow us to better understand whether a brief behavioral insomnia treatment can assist with suicidal ideation, a highly concerning issue among Veterans.