The authors use the British Workplace Employment Relations Survey to assess whether the combination of employee stock ownership (ESO) plans and participation in decision-making positively affect productivity or whether ESO alone affects employee productivity. By assessing the extent to which employees participate in ESOs and the quality of their decision-making, the authors provide a clearer and more nuanced picture of this relationship with productivity. On the one hand, results show that stock plans seem to need other forms of employee involvement and “voice” in the firm to be effective, especially when there is minority participation in the ESO plan. On the other hand, results indicate that a majority participation in the plan has an independent effect on productivity. Overall, the authors’ research challenges prevailing views about the complementarity regarding stock ownership and employee involvement practices.