Over the past few decades, small animal medicine has undergone remarkable advancements, with innovations that have significantly improved patient care and treatment outcomes. Among the most promising recent developments is antimicrobial photodynamic therapy (aPDT). This novel treatment modality is gaining recognition for its effectiveness in managing infectious diseases in dogs and cats, especially in the context of growing concerns about antimicrobial resistance (AMR). aPDT offers a promising alternative to traditional treatments, providing a new approach to combating infections that are increasingly resistant to conventional antimicrobials. Despite its considerable potential, aPDT remains underutilized in the field. This chapter explores the expanding role of aPDT in small animal practice, highlighting its diverse applications across various veterinary specialties. Research has demonstrated aPDT’s effectiveness in treating a range of dermatological conditions, including pyoderma, dermatophytosis, sporotrichosis, and otitis. These common and challenging conditions make aPDT’s efficacy particularly valuable. Moreover, aPDT’s application extends into veterinary dentistry, where it has shown promise in managing oral infections and papillomatosis. In addition, aPDT shows potential for treating infected wounds and osteomyelitis, serving as a valuable adjunct to conventional therapies. The therapy’s broad-spectrum antimicrobial activity, combined with minimal cytotoxicity to host tissues, enhances wound care and could help prevent post-surgical complications. This versatility underscores aPDT’s potential to complement and possibly revolutionize traditional therapeutic approaches. Ongoing research and clinical trials are crucial for refining aPDT protocols and expanding its applications in small animal medicine. As innovation continues, aPDT could play a pivotal role in managing infectious diseases in companion animals, offering targeted, effective, and resistance-free treatment options. Integrating aPDT into veterinary practice could help address the growing challenge of AMR and improve outcomes for a wide range of infectious conditions.