Lipid metabolism is the synthesis and degradation of lipids in cells. It is the breakdown or storage of fats for energy. Lipid metabolism disorders are illnesses where trouble occurs in breaking down or synthesizing fats. This chapter discusses the digestion and absorption of lipids, metabolism of simple lipids, metabolism of compound lipids, metabolism of fatty acids, metabolism of ketone bodies, metabolism of cholesterol, and metabolism of lipoproteins. The major lipids in the diet are triacylglycerols and the rest is made of phospholipids, cholesterol, cholesterolesters, and free fatty acids. Triacylglycerol is the predominant form of simple lipids, which are composed of glycerol esterified with three fatty acids. Lipid mainly as triacylglycerol can accumulate in the liver, called fatty liver. Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder worldwide. At the end of the chapter, there are 80 multiple choice questions are also given along with their explanatory answers.