Self-micro-emulsifying drug delivery systems (SMEDDS) are one of the proven methods to increase solubility and bioavailability of poorly soluble drugs. SMEDDS are isotropic mixtures, consisting of oils, surfactants, and sometimes co solvents. Designed formulations are used to improve the oral absorption of highly lipophilic compounds. Multiple lipid-based drug delivery systems are widely reported in the literature and they include simple oil solutions, coarse, multiple and dry emulsions, and more complex self-emulsifying, micro emulsifying or nano emulsifying drug delivery systems. The process of self-emulsification is dependent on diverse factors such as the nature of oil, surfactant, cosurfactant, oil/surfactant ratio, and the polarity of the emulsion. Considering the ease of large-scale production and the robustness of SMEDDS, several formulations are commercially available which utilize this technology. This article attempts to present an overview of SMEDDS along with their applications, compiled literature data, commercially available products, and their descriptions.