Theory and research surrounding employee voice in organizations have often treated high-involvement work practices (HIWPs) as substitutes for unions. Drawing on recent theoretical developments in the field of industrial relations, specifically the collective voice/institutional response model of union impact and research on HIWPs in organizations, the authors propose that these institutions are better seen as complements whereby greater balance is achieved between efficiency, equity, and voice when HIWPs are implemented in the presence of unions. Based on a national sample of Canadian organizations, they find employees covered by a union experience fewer intensification pressures under higher levels of diffusion of HIWPs such that they work less unpaid overtime, have fewer grievances, and take fewer paid sick days. Job satisfaction is maximized under the combination of unions and HIWPs.