Kaempferol isolated from the root of Zingiberaceae plants galangal and other Chinese herbal medicines have been reported to have anti-inflammatory properties. However, the anti-inflammatory effects of kaempferol on lipopolysaccharide (LPS)-induced mastitis are unknown and their underlying molecular mechanisms remain to be explored. The aim of this study was to evaluate the effects of kaempferol on LPS-induced mouse mastitis. The mouse model of mastitis was induced by injection of LPS through the duct of mammary gland. Kaempferol was injected 1 h before and 12 h after induction of LPS intraperitoneally. The present results showed that kaempferol markedly reduced infiltration of neutrophilic granulocyte, activation of myeloperoxidase (MPO), expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in a dose-dependent manner, which were increased in LPS-induced mouse mastitis. Furthermore, kaempferol suppressed the phosphorylation of nuclear factor-κB (NF-κB) p65 subunit and the degradation of its inhibitor IκBα. All results suggest that anti-inflammatory effects of kaempferol against the LPS-induced mastitis possibly through inhibition of the NF-κB signaling pathway. Kaempferol may be a potential therapeutic agent for mastitis.