We show that a firm’s profits under Cournot oligopoly can be increasing in the number of firms in the industry if wages are determined by (decentralised) bargaining in unionized bilateral oligopoly. The intuition for the result is that increased product market competition following an increase in the number of firms is mirrored by increased labor market rivalry which induces (profit-enhancing) wage moderation. Whether the product or labor market effect dominates depends both on the extent of union bargaining power and on the nature of union preferences. A corollary of the results derived is that if the upstream agents are firms rather than labor unions, then profits are always decreasing in the number of firms, as in the standard Cournot model. We also show that if bargaining is centralized then there is no wage moderation effect and wages are the same independent of the number of firms, as in the standard model with exogenous factor costs.