Antimicrobial peptides are part of the natural immune system of all plants and animals. This review focusses on ovine antimicrobial peptides because of the importance of the lamb industry in Australasia. The epithelial tissue β-defensins, respiratory surfactant-associated anionic peptides (SAAPs), and neutrophil cathelicidins are all described, and possible applications for these peptides are looked at, including use in ovine medicine, as biopreservatives, and as human therapeutics.