The intestinal environment is linked to an array of conditions and diseases, including osteoporosis. Human and animal studies indicate that probiotics can benefit intestinal health and may provide a useful therapeutic to prevent and/or treat bone loss. Probiotics are defined as live microorganisms that when administered in adequate amounts will confer a health benefit on the host. In this review, we will focus on (1) probiotics (definition, history, nomenclature, types), (2) the effects of probiotics on bone health, and (3) mechanisms of probiotic prevention of bone pathologies.