The main uses of surfactants in water-borne coatings are discussed. Special attention is put on the use of surfactants in latex polymerization and in post-emulsification of binders, such as alkyd resins. The advantage of polymerizable surfactants as emulsifier is pointed out and the use of atomic force microscopy (AFM) to observe differences in film properties between formulations based on polymerizable surfactants and on conventional surfactants is illustrated. The paper further discusses the problem of competitive adsorption between surfactants and between surfactant and associative thickener in paint formulations.