The DLVO theory represents an important framework to model interactions in aqueous colloidal suspensions and the respective aggregation rates. The theory assumes that the interaction forces can be well approximated by a superposition of van der Waals and double layer forces. In an symmetric system or in the case of homoaggreagtion, van der Waals forces are attractive and double layer forces repulsive. When one deals with asymmetric systems and heteroaggregation, the situation is can be more complex. While van der Waals forces are normally attractive, the double layer forces can be attractive, repulsive, or both. Moreover, effects of charge regulation can become important. DLVO theory is further capable to describe experimental situations relatively well. In some cases, this theory can describe interaction forces as well as aggregation rate constants quantitatively. Deviations may persist, however, especially at higher salt levels. These details are subject of current research.