Anxiety disorders are among the most prevalent psychiatric conditions. Despite many proven pharmacological and non-pharmacological treatments available, high rates of partial response and low rates of long-term remission remain. Ketamine has been receiving increasing attention as an interventional treatment modality in psychiatry, especially among refractory conditions, including major depressive disorder. There is limited yet growing evidence to support the use of ketamine in anxiety disorders. In this review of the literature, we present case reports, case series, and controlled trials demonstrating proof-of-concept for its potential role in the treatment of anxiety and anxiety spectrum disorders. Its unique mechanism of action, rapid onset, and high rate of response have driven its use in clinical practice. Ketamine is generally well tolerated by patients and has a limited side effect profile; however, the effects of long-term use are unknown. While there is a growing body of research and increasing clinical experience to suggest ketamine may have clinical applications in the treatment of refractory anxiety disorders, further research to determine long-term safety and tolerability is indicated.