Colloidal gels are defined as continuous networks of aggregated particles dispersed in a liquid phase. This type of gels can be formed by self-assembly of particles as the colloidal building blocks. Owing to reversible non-covalent interparticle interactions between these building blocks, colloidal gels can display self-healing behavior upon destruction of the gel network. For instance, self-healing organic colloidal gels have been developed by self-assembly of oppositely charged gelatin nanoparticles, where the mechanical properties and self-healing capacity of the colloidal gels strongly depended on the size of the colloidal building blocks. Furthermore, in order to develop colloidal gels with enhanced elasticity, combinations of organic and inorganic building blocks were recently explored. Since inter-particle forces determine the final properties of colloidal gels, several surface functionalization strategies are being explored to vary the adhesion forces between particles aiming at optimized self-healing behavior.