Proteus mirabilis is a major uropathogen with growing concern over its presence in animal products and the associated zoonotic transmission risks. As a gut commensal in both humans and animals, it is increasingly detected in wild, farm, and companion animals, as well as in animal-derived foods and related environments. This review summarizes current evidence on its distribution across these sources and explores potential transmission routes to humans. Special attention is given to reported genomic similarities and shared antimicrobial resistance patterns between animal and human isolates. The role of P. mirabilis in exacerbating intestinal inflammation further highlights its relevance beyond urinary infections. By revealing the epidemiology, pathogenic traits, and resistance profiles of animal-associated isolates, this review underscores the zoonotic potential of P. mirabilis and emphasizes the need for enhanced surveillance and research from a One Health perspective.