Microalgae are being promoted as a superior alternative feedstock for sustainable biofuel production and recently they are also being increasingly recognized as phytoremediation agents in bioremediation. Other than these, microalgae have been utilized as a sustainable feed in aquaculture for many years. The success of microalgae as a feed is based on the nutritional quality of microalgae, which are rich in protein, carbohydrates, fats, vitamins, minerals, and other beneficial biologically active components such as carotenoids and polyunsaturated fatty acids. Standards for the evaluation of microalgae include the assessment of various qualities such as digestibility, bioavailability, and toxicity analysis. This review provides comprehensive information regarding the current status and desirable characteristics of microalgae as a feed ingredient. Feed quality assessments such as protein quality, toxicological and microbiological analysis for microalgae are discussed. The techno-functional components of microalgae are presented in the feed perspective. The utilization of microalgae in various animal husbandry sectors and aquaculture are summarized. The advantages – disadvantages of microalgae as a feed is also presented, along with future research prospects. In short, this review will provide an overall view of the nutritional quality of microalgae and its beneficial application as a sustainable feed ingredient.