Insomnia during the perinatal period is common and has significant consequences when untreated. Cognitive behavioral therapy for insomnia (CBT-I), which targets the disorder’s “perpetuating” factors, is the first-line treatment for insomnia in adults. Randomized controlled trials (RCTs) document the efficacy of CBT-I in pregnant women when delivered face-to-face or via digital app; preliminary evidence for group-based delivery formats is also encouraging. The research on CBT-I during the postpartum period is more limited, but still promising. CBT-I can be delivered in its standard form, or with specific adaptations for perinatal populations, such as flexible time in bed restriction guidelines and additional educational content on sleep during the perinatal period. A few studies suggest that CBT-I may also benefit mental health outcomes.