Antimicrobial resistance poses a serious and growing threat to health worldwide, requiring innovative therapeutic strategies beyond conventional antibiotics. Gallium-containing porphyrin photosensitizers represent a promising “Trojan horse” approach that exploits the dependence of pathogens on iron and heme acquisition systems. Due to gallium’s unique ability to mimic iron while disrupting redox processes critical to pathogens, gallium porphyrins can selectively interfere with the metabolism and survival of microorganisms. This chapter explores the therapeutic potential of these compounds, discussing their efficacy against a range of bacterial pathogens, including intracellular species that evade traditional treatments. Particular emphasis is placed on light-dependent mechanisms of action, in which gallium-based photosensitizers generate reactive oxygen species that enhance antimicrobial activity. Despite promising results, challenges remain, such as optimizing delivery, minimizing side effects, and overcoming microbial adaptation. Overall, gallium porphyrin photosensitizers offer a multifaceted and innovative strategy that may help address the urgent problem of antimicrobial resistance.