Osteoclasts, which are derived from monocyte-macrophage precursors, are exclusive bone resorption cells. Limited evidence indicates that a class of small non-coding single-stranded RNAs known as "microRNAs" (miRNAs) is also involved in bone resorption. Although various miRNAs regulate cell proliferation and differentiation, few miRNAs have been reported to play a key role in the regulation of osteoclast differentiation. In this short review, the biology and functional mechanisms of miRNAs in osteoclastogenesis are summarized. The profiling, function, and target prediction of miRNAs are discussed as well.