Greek yogurt is a thick, creamy yogurt that can add flavor and texture to foods. Other benefits of Greek yogurt include boosting bone health, building muscle mass, and lowering the risk of certain health conditions. Greek yogurt differs from other yogurts because it goes through a straining process to remove the whey. Whey is a liquid that contains lactose, a natural sugar found in milk.
Some manufacturers add thickening agents to regular yogurt and market it as "Greek-style" yogurt, which may not share the same health benefits as Greek yogurt. Also, low or no-fat Greek yogurt may not share the same health benefits as traditional Greek yogurt. Read more on Wikipedia