Insomnia is common among Veterans with Gulf War Illness (GWI). Moreover, untreated insomnia is associated with significant medical and psychiatric morbidity. Cognitive Behavioral Therapy for Insomnia (CBTi) is a multicomponent treatment that seeks not only to teach patients about sleep and factors affecting sleep (e.g., circadian rhythm, age, social and work schedule) but the therapist will also to work with the patient toward minimizing unwanted arousal at bedtime and altering sleep habits to increase sleep propensity and regularity.