•Bmp5-mutant mice have low hepcidin in early life and exhibit mild iron loading under low- or high-iron or Bmp6-heterozygous conditions.•Bmp5 mutations exacerbate hemochromatosis and abrogate hepcidin responses to iron in Bmp6-knockout mice. Display omitted Hepcidin is the master regulator of systemic iron homeostasis. The bone morphogenetic protein (BMP) signaling pathway is a critical regulator of hepcidin expression in response to iron and erythropoietic drive. Although endothelial-derived BMP6 and BMP2 ligands have key functional roles as endogenous hepcidin regulators, both iron and erythropoietic drives still regulate hepcidin in mice lacking either or both ligands. Here, we used mice with an inactivating Bmp5 mutation (Bmp5se), either alone or together with a global or endothelial Bmp6 knockout, to investigate the functional role of BMP5 in hepcidin and systemic iron homeostasis regulation. We showed that Bmp5se-mutant mice exhibit hepcidin deficiency at age 10 days, blunted hepcidin induction in response to oral iron gavage, and mild liver iron loading when fed on a low- or high-iron diet. Loss of 1 or 2 functional Bmp5 alleles also leads to increased iron loading in Bmp6-heterozygous mice and more profound hemochromatosis in global or endothelial Bmp6-knockout mice. Moreover, double Bmp5- and Bmp6-mutant mice fail to induce hepcidin in response to long-term dietary iron loading. Finally, erythroferrone binds directly to BMP5 and inhibits BMP5 induction of hepcidin in vitro. Although erythropoietin suppresses hepcidin in Bmp5se-mutant mice, it fails to suppress hepcidin in double Bmp5- and Bmp6-mutant males. Together, these data demonstrate that BMP5 plays a functional role in hepcidin and iron homeostasis regulation, particularly under conditions in which BMP6 is limited. Hepcidin is the master regulator of iron homeostasis and is regulated by bone morphogenetic protein (BMP) signaling in response to iron loading, iron deficiency, and erythropoietic drive. This regulation is largely a reflection of BMP6 and BMP2, but the role of BMP5 has not been defined. Xiao et al probed the contribution of BMP5 signaling to iron homeostasis, demonstrating that it also has a role in hepcidin regulation. BMP6 heterozygous or homozygous-null mice have increased iron loading that is further amplified with concomitant BMP5 knockout. This further elucidates the complex process of hepcidin regulation and iron metabolism.