Nanotechnology has emerged as a revolutionary asset in fighting microbial infections, presenting innovative approaches via nanoparticles that possess strong antimicrobial characteristics. This chapter offers a comprehensive examination of different kinds of nanoparticles—such as silver nanoparticles (AgNPs), titanium dioxide (TiO₂), zinc oxide (ZnO), and iron oxide (Fe₃O₄)—along with their modes of action against a wide range of pathogens. The section details the physicochemical characteristics that affect nanoparticle effectiveness, including dimensions, form, surface charge, and the ratio of surface area to volume. The key mechanisms addressed involve the production of reactive oxygen species (ROS), disturbance of microbial membranes, and the liberation of metal ions. The chapter further examines uses in veterinary medicine, food storage, surface sanitation, and coatings for medical devices. Particular focus is placed on polymeric nanoparticles, including PLGA and PEG-based systems, for precise delivery and prolonged antimicrobial effects. Issues such as antimicrobial resistance (AMR), toxicity issues, and regulatory constraints are thoroughly analyzed, emphasizing the necessity for uniform testing methods and studies on long-term effects. Additionally, new studies on the combined effects of nanoparticles and traditional antibiotics are examined, highlighting potential therapeutic pathways. The chapter ends with a call for collaborative strategies to enhance nanoparticle design for safe, efficient, and sustainable antimicrobial solutions.