The occipital nerve block involves the injection of a local anesthetic and possibly a corticosteroid near the occipital nerves at the base of the skull and aims at providing relief from chronic headaches by temporarily numbing or reducing inflammation around the occipital nerves. It has proven to be efficacious in treating chronic headaches, especially those that are refractory to medication; it is both diagnostic and therapeutic with symptom abatement from weeks to months. Occipital nerve blocks can be utilized alone or with standard-of-care therapy for various other headache conditions, such as cluster headaches, episodic headaches or chronic migraines. This review aims to provide an analysis of the world literature on the role of occipital nerve block (ONBs) in the treatment of headaches, including the procedure, efficacy and safety of ONB, and to elucidate the current understanding of ONBs. ONBs demonstrate diagnostic and therapeutic benefits with symptom abatement for weeks to months. Outcomes are generally well tolerated, with minimal side effects associated mainly with the injection process, including numbness, tingling and local discomfort. Greater occipital nerve blocks are an efficacious procedure to treat chronic headache symptoms, and future research should include additional longitudinal follow-up results and interactions of ONBs with other headache treatments.