Antimicrobial photodynamic therapy (aPDT) represents a novel and innovative approach in veterinary medicine, offering a noninvasive and effective means to treat a wide array of diseases across multiple species. By harnessing the photochemical activation of photosensitizers (PSs) to generate reactive oxygen species, aPDT targets and eradicates diverse pathogens, including bacteria, fungi, protozoa, viruses, and pathogenic algae. This method has shown promise in addressing infections that are increasingly resistant to conventional antimicrobial treatments, positioning aPDT as a valuable tool in the fight against antimicrobial resistance. The versatility of aPDT is evident in its application across various clinical scenarios, ranging from the treatment of localized infections to its potential role in broader antimicrobial stewardship initiatives. However, despite the promising outcomes observed in different studies, several critical challenges hinder the widespread adoption and optimal utilization of aPDT in veterinary practice. Among these challenges are the paucity of robust clinical studies that can definitively establish the efficacy and safety of aPDT across different species and conditions. The vast diversity of animal species, each with unique physiological and pathological traits, further complicates the standardization of treatment protocols. Additionally, the variability in PS toxicity, the need for precise light parameter adjustments, and the current lack of comprehensive training for veterinary professionals in aPDT techniques pose significant barriers to its mainstream adoption. This chapter offers a detailed examination of these limitations, highlighting the key areas that require further research and development. By addressing these challenges, the veterinary field can more effectively harness the potential of aPDT, ultimately enhancing the quality of care and treatment outcomes for animal patients. Through continued exploration and innovation, aPDT could become an integral part of modern veterinary practice, contributing to the advancement of animal health and well-being.