AbstractDibutyltin (DBT) is used to stabilize polyvinyl chloride plastics (including pipes that distribute drinking water) and as a de‐worming agent in poultry. DBT is found in human blood, and DBT exposures alter the secretion of tumor necrosis factor alpha and interferon gamma from lymphocytes. Interleukin (IL)‐1β is a proinflammatory cytokine that regulates cellular growth, tissue restoration and immune response regulation. IL‐1β plays a role in increasing invasiveness of certain tumors. This study reveals that exposures to DBT (24 h, 48 h and 6 days) modify the secretion of IL‐1β from increasingly reconstituted preparations of human immune cells (highly enriched human natural killer cells, monocyte‐depleted [MD] peripheral blood mononuclear cells [PBMCs], PBMCs, granulocytes and a preparation combining both PBMCs and granulocytes). DBT altered IL‐1β secretion from all cell preparations. Higher concentrations of DBT (5 and 2.5 μm) decreased the secretion of IL‐1β, while lower concentrations of DBT (0.1 and 0.05 μm) increased the secretion of IL‐1β. Selected signaling pathways were examined in MD‐PBMCs to determine if they play a role in DBT‐induced elevations of IL‐1β secretion. Pathways examined were IL‐1β converting enzyme (caspase 1), mitogen‐activated protein kinases and nuclear factor kappa B. Caspase 1 and mitogen‐activated protein kinase pathways appear to be utilized by DBT in increasing IL‐1β secretion. These results indicate that DBT alters IL‐1β secretion from human immune cells in an ex. vivo system utilizing several IL‐1β regulating signaling pathways. Thus, DBT may have the potential to alter IL‐1β secretion in an in vivo system. Copyright © 2016 John Wiley & Sons, Ltd.