Background Insomnia affects up to one-third of US adults and is a significant health challenge with an estimated economic burden of up to $100 billion annually. Cognitive behavioral therapy (CBT) for insomnia (CBT-I) is the recommended first-line treatment, but access is limited due to a shortage of trained therapists. Digital CBT-I offers an effective alternative that may enhance accessibility and reduce higher healthcare costs associated with insomnia. Objective To evaluate the US healthcare cost-savings of digital CBT-I compared with standard-of-care control. Methods A retrospective difference-in-differences analysis compared 1-year preinitiation and post-initiation healthcare costs for 11 027 individuals receiving SleepioRx (FDA-cleared digital CBT treatment for insomnia disorder) compared with 1:1 exact matched controls with insomnia receiving standard care (n = 10 770). Commercial and Medicare claims were adjusted for comorbidities, index year, and baseline utilization. Results Digital CBT-I was associated with statistically significant mean annual total cost savings of $2083 (95% CI, $1508-$2657, P  < .001) per person, equating to a 42% reduction in costs with SleepioRx relative to matched controls who received standard of care (medications for insomnia). Discussion Digital CBT-I was associated with substantial cost savings for payers. The integration of guideline-concordant treatment through digital delivery into standard care pathways offers a promising strategy to address the clinical and economic challenges of insomnia, supporting more efficient resource allocation. Conclusions Findings suggest that implementing digital CBT-I at scale may lead to decreased costs for healthcare payers, relative to the current standard of care, while improving access to effective insomnia treatment.