MicroRNAs (miRNAs) are a group of small noncoding RNA (ribonucleic acid) molecules which target gene expression through a sequence-specific manner. Advances in research have demonstrated that thanks to this capacity miRNAs are involved in several biological processes, among which we find also the complex process of bone remodeling. Over the last years, researchers have elucidated not only their role in all the key points of bone remodeling but have also demonstrated that their expression or their downregulation could be associated to the progression of several bone diseases, including osteoporosis, osteonecrosis, multiple myeloma bone disease, osteomyelitis, thalassemia bone disease, osteogenesis imperfecta, atrophic nonunion, rheumatoid arthritis, chondrosarcoma, and osteosarcoma. In fact, in the last decades it has been demonstrated how miRNAs are involved also in multiple pathological mechanisms, including alteration of osteoclastogenesis, metastasis, bone loss and osteosarcoma, and chondrosarcoma cell proliferation. Therefore, in this chapter we summarize the recent findings related to the role of miRNAs in physiological processes of osteoblastogenesis and osteoclastogenesis, in osteocytes physiology, and in several bone diseases (i.e., osteoporosis, osteonecrosis, multiple myeloma bone disease, osteomyelitis, thalassemia bone disease, osteogenesis imperfecta, atrophic nonunion, rheumatoid arthritis, chondrosarcoma, and osteosarcoma), highlighting their potentiality as theragnostic targets for each of the these ailments.