Bone morphogenetic proteins (BMPs), members of the transforming growth factor-β family, were first identified as potent inducers of ectopic bone formation when implanted into muscle tissue. Subsequent studies have demonstrated that BMPs play important roles during developmental processes, including cell proliferation, differentiation, and apoptosis. Furthermore, recent studies have shown that BMPs are also involved in the initiation and/or progression of various diseases, such as skeletal diseases, cancer, and vascular diseases. Nuclear factor κ light-chain enhancer of activated B cells (NF-κB) was originally identified as a transcription factor that bound to the enhancer region of the immunoglobulin κ light-chain promoter in B cells. A wide range of stimuli, including inflammatory cytokines and bacterial and viral products, activate the NF-κB pathway, leading to the expression of NF-κB target genes. NF-κB also has functions in multiple biological processes, such as immune and inflammatory responses, cell differentiation, cellular stress responses, and cancer development. Recent findings have demonstrated that BMP and NF-κB signaling agonistically or antagonistically regulate bone development, cancer development, and vascular diseases. This review describes the role of BMPs and NF-κB in bone development, cancer development, and vascular diseases with special attention given to concepts that have emerged in recent years.