Owing to its diverse range of bioactive compounds, Ganoderma lucidumhas garnered significant research attention for health promotion and disease prevention. Ganodermanondiol, which has a triterpenoid structure, is one of the major active compounds of G. lucidum. In the present study, the anti-inflammatory effects of ganodermanondiol were investigated to evaluate its usefulness as a functional ingredient. Ganodermanondiol (0.5–2 g/mL) significantly inhibited the production of nitric oxide (NO), the expression of the cytokines tumor necrosis factor (TNF)??and interleukin 6 (IL-6), and the expression of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) in lipopolysaccharide-induced RAW 264.7 (murine macrophage) cells. Ganodermanondiol (0.5–2 g/mL) also inhibited the phosphorylation of mitogen-activated protein kinase (MAPK) signal molecules, including p38 and c-Jun N-terminal protein kinase (JNK) in RAW 264.7 cells. Ganodermanondiol significantly inhibited the essential factors involved in the inflammatory responses of RAW 264.7 cells and would, therefore, serve as a potential prophylactic and therapeutic agent for immune-related diseases.