Objective: To review the pharmacology and clinical data for brexpiprazole in schizophrenia and major depressive disorder (MDD). Data Sources: An English-language literature search using PubMed and MEDLINE was performed using the term brexpiprazole. All articles containing human clinical trial data published up to September 2016 were evaluated for inclusion as well as information from the manufacturer's product labeling. Study Selection/Data Extraction: Phase 3 trials for brexpiprazole were evaluated. Key in vitro and animal data were incorporated into the pharmacology and pharmacokinetic sections where appropriate. Data Synthesis: Four phase 3 trials have evaluated the use of brexpiprazole as a primary therapy for schizophrenia or as an antidepressant adjunct for MDD. For its schizophrenia indication, brexpiprazole was studied in 2 placebo-controlled trials of approximately 1300 patients, with 4 mg of brexpiprazole consistently showing superiority over placebo. For MDD, brexpiprazole was compared with placebo as an adjunct to antidepressants in approximately 1000 patients who had failed trials of I to 3 prior antidepressants. The 2-mg and 3-mg dosages of brexpiprazole showed consistent superiority over placebo in the MDD trials. Common treatment emergent adverse effects included akathisia and weight gain. Conclusions: Brexpiprazole showed efficacy for the treatment of schizophrenia in the range of 2 to 4 mg/d and as an adjunct to antidepressant therapy in MDD when dosed at 2 to 3 mg/d. Advantages of this drug include once-daily dosing, good tolerability, and lack of effect on sexual function. Disadvantages include the lack of long-term safety data and potentially high cost.