**Abstract**

Lignosulfonates are biobased surfactants and specialty chemicals. Due to their amphiphilic nature, they can be utilized in many technical applications, such as plasticizers, dispersants, stabilizers, and agrochemical formulations. Here, their ability to stabilize emulsions plays an important role. This chapter hence explains the fundamentals of emulsion stabilization with lignosulfonates. First, basic concepts are introduced along with the production and chemical make-up of lignosulfonates. Second, the interfacial activity is discussed. Parameters that affect interfacial activity and emulsion stabilization efficiency of lignosulfonates are furthermore treated. Such parameters may include salinity, pH, the presence of cosolvents and cosurfactants. Third, the underlying mechanisms of emulsion stabilization are outlined. The goal of this chapter is to introduce the reader to important fundamentals, and to draw the link between basic research and industrial practice.

**Keywords:** lignin, lignosulfonates, surfactant, emulsion, dispersion, stabilizer, interfacial activity, colloid chemistry
