["International Journal of Management Reviews, EarlyView. ", "\nAbstract\nAs the stalling progress suggests, gender equality remains out of reach without the active and effective engagement of men ‘leaning in together’ with women, as partners in change. The literature increasingly recognizes men's allyship in work organizations as a vital force in the pursuit of gender equality, yet reaches different conclusions about its effectiveness. This paper presents a systematic and integrative synthesis of 110 articles and other sources on men's allyship for gender equality in work organizations, clarifying its triggers, barriers, behaviours and outcomes. We draw on ambivalence theory to develop the ‘Men's Coping with Allyship Ambivalence’ framework, which reconciles inconsistent findings by showing how ambivalence due to men's mixed cognitions and/or emotions toward allyship shapes four distinct allyship coping strategies. These strategies, shaped by internal and external barriers and triggers, lead to varied behaviours and outcomes across organizations. Our framework contributes a fresh and critical perspective by positioning ambivalence as central to understanding men's engagement in gender equality efforts. In doing so, it challenges linear accounts of allyship and opens new directions for theory, empirical research and practice aimed at fostering more reflexive and durable forms of men's allyship in organizations.\n"]