Abstract: The global kiwifruit industry has expanded rapidly, but bacterial canker remains one of the most destructive diseases, severely constraining high-quality, high-yield production and causing substantial economic losses in major growing regions. This review synthesizes current knowledge of bacterial canker resistance in Actinidia, with an emphasis on differences between wild and cultivated germplasm and the identification of elite resistant resources for breeding. Resistance mechanisms are examined at physiological and molecular levels. At the physiological level, structural barriers, hormone-mediated defense regulation, and secondary metabolites are discussed as key components of responses in Actinidia to bacterial canker infection. At the molecular level, resistance-associated genes and immune signaling components are examined to clarify how coordinated defense networks contribute to pathogen recognition, signal transduction, and downstream resistance responses. By integrating germplasm evaluation with physiological and molecular evidence, this review outlines a multi-level defense framework for Actinidia resistance to bacterial canker. These insights provide a theoretical basis for environmentally sustainable disease management and resistance-oriented breeding, supporting the development of resilient cultivars and the long-term sustainable growth of the kiwifruit industry.