© 2016, Springer-Verlag Berlin Heidelberg. Purpose: Olanzapine is a potent antipsychotic medication that inhibits a wide variety of receptors. It has been used in trials for the prophylaxis and rescue of chemotherapy-induced nausea and vomiting (CINV). This study systematically investigates the efficacy of olanzapine in relation to other antiemetics in the prophylaxis and rescue of CINV. Methods: A literature search of Ovid MEDLINE, EMBASE, and CENTRAL was conducted to identify randomized controlled trials (RCTs) comparing olanzapine to other standard antiemetics for either prevention or rescue. The primary endpoints were the percentage of patients achieving no emesis or no nausea, in the acute, delayed, and overall phases. Results: Ten RCTs in the preventative setting and three RCTs in the breakthrough setting were identified. Subgroup analysis demonstrated a similar degree of benefit from a 5- and 10-mg dose of olanzapine for the no emesis endpoint in the overall phase. In the prophylaxis setting, olanzapine was statistically superior in five of six endpoints and clinically superior in four of six endpoints. In the breakthrough setting, olanzapine was statistically and clinically superior in the only endpoint analyzed: no emesis. Conclusion: Olanzapine is more efficacious than other standard antiemetics for the rescue of CINV and its inclusion improves control in the prevention setting. Given the possible reduction in side effects, the use of a 5-mg dose of olanzapine should be considered. Future RCTs should compare the 5-mg versus the 10-mg dosages further and report on the efficacy and percentage of patients developing side effects. Further analyses should be done without the influence of corticosteroids.