Background: The balance between bone formation and bone resorption which is attributed to osteoblast and osteoclast is required to maintain skeleton homeostasis. Osteoclast differentiation is regulated by a tumor necrosis factor–receptor activator of nuclear factor NF-kB ligand (RANKL). The dysregulation of bone-resorbing osteoclast differentiation can lead to osteoporosis. The adverse effects of the long-term use of bone resorption inhibitors are of concern and so the development of new osteoporosis therapy treatment is desirable. Objective: In this study, 67 plants (70 samples) were screened for osteoclastogenesis inhibitory activities on RAW264.7 mouse macrophages and bone marrow-derived macrophages (BMMs). Materials and Methods: The RAW264.7 cells and the BMMs isolated from male ICR mice were treated with various doses of plant extracts and TRAP histochemical staining of the cells was performed. TRAP-positive multinucleated cells were photographed under microscopy to observe the effects of the extracts on osteoclast differentiation. Results: Among 70 methanol extracts, we found that nine samples exhibited significant inhibitory effects in RANKL-induced osteoclast differentiation. They included Aleurites moluccana (S16 and S17), Aporosa dioca (S19), Antidesma bunius (S21), Cinnamomum balansae (S32), Macrosolen cochinchinensis (S41), Pinus kesiya (S52), Photinia benthamiana (S54), and Mischocarpus pentapetalus (S59). Conclusion: In the present study, 70 plant extracts were screened for the osteoclastogenesis inhibitory effects in RAW264.7 murine macrophages and BMMs. Nine extracts have the potential as effective agents against osteoclastogenesis. This is the first report on the anti-osteoclastogenetic activity of these plants.