Osteoporosis and fragility fractures are a growing problem for our aging population with around 1 in 2 women and 1 in 5 men suffering from an osteoporotic fracture during their lifetime. Although there are established factors that can reduce the risk of fracture such as maintaining physical activity, ceasing smoking, and adequate vitamin D status, and intakes of calcium; dietary mechanisms are less well established. The relevance of the flavonoid group of bioactive compounds found in fruits and vegetables has been less investigated. Two human epidemiologic studies in women found positive associations between total dietary flavonoid intake and bone mineral density. Flavonoids may protect against bone loss by upregulating signaling pathways that promote osteoblast function, by reducing the effects of oxidative stress or chronic low-grade inflammation. The limitations of the existing research are explored in the manuscript and it is concluded that further research is needed, in this promising area.