Whey protein is a derived by-product from cheese manufacturing and has many health benefits due to its high-level content of bioactive peptides, such as β-lactoglobulin, α-lactalbumin, serum albumin, immunoglobulin, and lactoferrin. These proteins have antioxidant characteristics that reduce hypertension, cancer, hyperlipidemia, and virus contagious. In addition, whey protein is utilized to lessen the inflammatory bowel disease. In this review, we highlighted the characteristics, applications, functional properties of whey proteins.