In this study, we found that alpha-pinene (α-pinene) exhibits anti-inflammatory activity through the suppression of mitogen-activated protein kinases (MAPKs) and the nuclear factor-kappa B (NF-κB) pathway in mouse peritoneal macrophages. α-Pinene is found in the oils of many coniferous trees and rosemary. We investigated the inhibitory effects of α-Pinene on inflammatory responses induced by lipopolysaccharide (LPS) using mouse peritoneal macrophages. α-Pinene significantly decreased the LPS-induced production of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and nitric oxide (NO). α-Pinene also inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions in LPS-stimulated macrophages. Additionally, the activations of MAPKs and NF-κB were attenuated by means of α-pinene treatment. These results indicate that α-pinene has an anti-inflammatory effect and that it is a potential candidate as a new drug to treat various inflammatory diseases.