Osteoporosis is the leading underlying cause of fractures, particularly in postmenopausal women, due to the loss of estrogen-mediated suppression of bone resorption. More than 50% of adults 50 years of age or older are estimated to have osteoporosis. Osteoclast which is main target for treatment of osteoporosis is originated from hematopoietic cell line. Aloe has been widely used in worldwide country as a coadjuvant medicine. Extracts of the leaves of Aloe have been used in condition to improve dermatologic problem such as seborrheic dermatitis, aphthous stomatitis, xerosis, lichen planus and has been known to exert anti-inflammatory, anti-oxidant and anti-tumor effects. However, despite the popularity of aloe as a plant food supplements, the evaluation of its efficacy as a possible therapeutic option for osteoporosis remains scarce. Thus, we evaluated the effect of Aloe on receptor activator of nuclear factor-${kappa}B$ ligand (RANKL)-induced osteoclast differentiation. Here we found that Aloe significantly inhibited osteoclast differentiation induced by RANKL. Aloe suppressed the activation of p38 pathway and $NF{kappa}B$ in bone marrow macrophages (BMMs) treated with RANKL. Also, Aloe significantly inhibited the mRNA expression of c-Fos, tartrate-resistant acid phosphatase (TRAP), osteoclast-associated receptor (OSCAR), nuclear factor of activated T cells (NFAT)c1 and cathepsin K in BMMs treated with RANKL. Particularly, Aloe greatly inhibited the protein expression of c-fos and NFATc1. Taken together, our results suggested that Aloe may be useful tool for treatment of osteoporosis by inhibition of osteoclast differentiation.