--- - |2+ The zafirlukast has been reported to be anti‐inflammatory and widely used to alleviate the symptoms of asthma. However, its influence on insulin secretion in pancreatic β‐cells has not been investigated. Herein, we examined the effects of zafirlukast on insulin secretion and the potential underlying mechanisms. Among the cysteinyl leukotriene receptor 1 antagonists, zafirlukast, pranlukast, and montelukast, only zafirlukast enhanced insulin secretion in a concentration‐dependent manner in both low and high glucose conditions and elevated the level of [Ca2+]i, further activating Ca2+/calmodulin‐dependent protein kinase II (CaMKII), protein kinase B (AKT), and extracellular signal‐regulated kinase (ERK) signaling. These effects were nearly abolished by the L‐type Ca2+ channel antagonist nifedipine, while treatment with thapsigargin, a sarco/endoplasmic reticulum Ca2+ ATPase inhibitor, did not have the same effect, suggesting that zafirlukast primarily induces the entry of extracellular Ca2+ rather than intracellular Ca2+ from the endoplasmic reticulum. Zafirlukast treatment resulting in a significant drop in glucose levels and increased insulin secretion in C57BL/6J mice. These findings will contribute to an improved understanding of the side effects of zafirlukast and potential candidate for a therapeutic intervention in diabetes. - Journal of Cellular Physiology, Volume 233, Issue 11, Page 8701-8710, November 2018.