This chapter provides basic information about various alternative sources of proteins, which are vital nutrient for normal growth and functioning of human body. Animal-derived proteins, such as meat, poultry, dairy, eggs etc., are the mainstay of today’s diet and an integral part of global food production. However, owing to continuously rising global population which has been projected to reach 9.7 billion in coming 30 years, with an increase of 80% in meat consumption. A sustainable option to feed this rising population comes from various alternative protein sources which has been briefly discussed in the chapter. Moreover, increasing awareness of people about healthy eating choices also favors consumption of less animal-based products as majority of them are high in fat content contributing significantly to increasing burden of degenerative diseases like diabetes, cardiovascular diseases etc., worldwide. So, in order to meet out this increasing demand of protein, various sources of plant derived proteins can be a promising source in the near future for example, higher yields of pseudocereals can facilitate the production of protein products with high nutritional value and physico-chemical properties for a wide range of foods. In addition, the by-products obtaining after extraction process of various oilseeds has great potential to be considered as a major source of protein ingredients in the future. Mycoproteins are another emerging source of proteins. They are increasingly gaining popularity as new alternative of meat which signifies its successful introduction and commercialization as a promising protein source. Further research activities are required which focuses on reducing production costs and increasing the functionality and sensory profile of mycoproteins.