Owing to emerging global threats such as viral pandemics and the rise of antibiotic resistance, there is an urgent need for novel approaches to combat drug-resistant pathogens. Antimicrobial peptides (AMPs), also known as cationic host defense peptides (CHDPs), are considered promising candidates because of their ability to target various pathogenic microorganisms both directly and indirectly. These functionally versatile molecules modulate host immune responses by activating multiple signaling pathways simultaneously. The unique mechanisms of interaction within the pathogen-host system, combined with relatively straightforward biosynthesis, make AMPs viable alternatives to traditional antibiotics. Vitamin D is a key endogenous factor that regulates the biosynthesis and activity of AMPs, particularly cathelicidin and defensins. This chapter focuses on the interplay between vitamin D and antimicrobial peptides, highlighting recent advances in understanding their synergistic protective effects and potential clinical benefits.