This article explores employee voice within the specific institutional arrangement of double-breasting. Double-breasting is when multi-plant organizations recognize trade unions in some company sites, with non-union arrangements at other company plants, or where a unionized firm acquires a new site that it then operates on a non-union basis. We examine three research questions in four separate case study organizations that operate employee voice double-breasting arrangements across 16 workplace locations on the island of Ireland. These questions consider employer motives for double-breasting, the practices that characterize double-breasting employee voice, and the micro-political implications of double-breasting. The article contributes to knowledge on the emergence and impact of double-breasting and employee voice systems. We subsequently advance two theoretical propositions: the first theorizing employer motives for double-breasting, and the second explaining the extent to which the practice of double-breasting is durable over time.