This narrative review argues that non-thermal biological effects of extremely low and microwave frequency EMFs may be mediated by activation of voltage-gated calcium channels (VGCCs). It cites 23 studies in which VGCC blockers reportedly block or reduce diverse EMF effects and proposes downstream Ca2+/calmodulin-dependent nitric oxide signaling. The review discusses both potential therapeutic effects (e.g., bone growth stimulation) and potential adverse effects via oxidative stress pathways, including a reviewed example of DNA single-strand breaks.