Nanotechnology opens new possibilities for the development of antimicrobial materials. Of particular interest are graphene-based nanomaterials, which possess unique antimicrobial properties and offer multiple routes for functionalization into advanced nanocomposite materials. In this chapter, we review the current state of knowledge regarding the fundamental aspects of the antimicrobial interactions of graphene and graphene-based materials. Then, an overview of the multiple graphene-based composite materials developed for antimicrobial applications is provided, with an analysis of the different chemical functionalization routes used to modify graphene and graphene oxide with biocidal compounds. An analysis of the potential of graphene-based nanomaterials in the development of novel antimicrobial surfaces and coatings is also conducted, with an emphasis on the field of membrane processes, where significant developments have been made. Finally, promising avenues for material development are identified and critical questions surrounding graphene-based nanomaterials are discussed, providing a guide for future development and application of antimicrobial graphene-based materials.