Drugs are frequently administered by the oral route. However, greater than 40% of new chemical entities show poor aqueous solubility which results in unsatisfactory oral drug delivery. Now a day, lots of attention has been pointed on self emulsifying drug delivery systems (SEDDS) to develop the oral bioavailability of poorly aqueous soluble drugs. SEDDS are isotropic mixtures of oil, surfactants, solvents and co solvents/surfactants. The main features of these systems are their capacity to form fine oil in water (o/w) emulsions or micro emulsions upon mild agitation following dilution by an aqueous phase through the gastrointestinal tract for lipophilic drugs, which shows dissolution rate limited absorption, SEDDS may be a promising strategy to modify the rate and extent of oral absorption. This article gives an overview of potential advantages of SEDDS and its composition. Types of SEDDS and brief mechanism of action, introduction to ternary phase diagram and its use in SEDDS, various dosage forms available for SEDDS. The characterization of SEDDS and application of SEDDS is also introduced, with special attention given on the development of solid self emulsifying delivery system and dosage form of SEDDS and its future trends