Background: Glutamate is a major excitatory neurotransmitter, while γ-aminobutyric acid (GABA) is a predominant inhibitory neurotransmitter in the central nervous system. This GABA-glutamate imbalance is thought to play a role in the development of anxiety. Acamprosate calcium is thought to restore this chemical imbalance in alcohol withdrawal. Objective: To examine acamprosate calcium as augmentation therapy for treatment of anxiety. Methods: This 8-week, open-label study was designed to evaluate patients with anxiety who were stable on current medications (selective serotonin-reuptake inhibitors and serotonin-norepinephrine-reuptake inhibitors) but still symptomatic. Acamprosate was dosed at 1998 mg/day. Assessments included the Hamilton Rating Scale for Anxiety (HAM-A) and the Hospital Anxiety and Depression Scale. Results: Thirteen patients enrolled in the study and received study medication. Acamprosate reduced anxiety symptoms (mean HAM-A score reduction to 8.87 from a baseline of 20). Sixty-two percent of patients receiving acamprosate achieved remission (HAM-A score ≤7). Modal dose was 1998 mg/day (range 999-1998). The most commonly reported adverse events were nausea (n = 1), gastrointestinal upset (n = 1), and increased dream activity (n = 1). Conclusions: Acamprosate calcium may be effective augmentation therapy in patients with treatment-resistant anxiety.