The development of surface-active ionic liquids (SAILs) has gained significant interest in recent decades and has successfully replaced the currently utilized conventional surfactants. Due to the amphiphilic character of the SAILs, they have become remarkable surfactants and are particularly important for commercial and field usage. SAILs formed microemulsions and have shown potential in various sectors, including oil recovery and dispersion. The effectiveness of SAILs was measured by their capacity to develop microemulsions. Moreover, it was stated that efficient SAILs could develop a stable microemulsion throughout extended periods at low surfactant concentrations. Similarly, normal ionic liquids (ILs) gained significant attraction as a dispersion medium for colloidal systems as a potential alternative to volatile organic solvents. Colloidal stability is a crucial parameter for evaluating the characteristics and efficacy of colloidal systems. Therefore, the main emphasis is critically discussing the fundamental studies on colloidal stability. Considering the importance and significance of surfactant and colloidal behavior of ILs, this chapter describes these properties by employing recent relevant literature on the topic. The aggregation properties of SAILs alone and the mixed systems of SAILs and conventional surfactants are discussed with their usage in environmental clean-up. Moreover, the colloidal stability of SAILs, as well as the important factors that influence colloidal stability, are discussed in this chapter.