We have investigated the role of TNF‐α in mast cell‐mediated late airway hyperresponsiveness (AHR) using mast cell‐deficient WBB6F1‐W/W^v (W/W^v) mice in a murine model of asthma, which exhibits a biphasic increase in AHR. TNF‐α levels in the airway and magnitude of late AHR in response to airway allergen challenge were severely impaired in W/W^v mice compared to their littermates. In addition to TNF‐α, cytosolic phospholipase A₂ (cPLA₂) phosphorylation and enzymatic activity in the lungs were also impaired in W/W^v mice. Either anti‐TNF‐α antibody or an inhibitor of cPLA₂ abolished late AHR in congeneic +/+ mice. Intratracheal administration of TNF‐α resulted in increases in late AHR, cPLA₂ phosphorylation, cPLA₂ activity, and phosphorylation of mitogen‐activated protein kinases. Mast cell replacement restored airway TNF‐α level, cPLA₂ phosphorylation and enzymatic activity in the lungs as well as late AHR in W/W^v mice. These data indicate that mast cells play a key role in the development of late AHR through liberation of TNF‐α.