Citrus by-products, such as peels, seeds, and pomace, serve as significant sources of dietary fiber, encompassing both soluble and insoluble fibers. Citrus peels, particularly those derived from oranges, lemons, and other citrus fruits, are notably high in dietary fiber content. This chapter delves into the enzymatic–gravimetric method, which provides a reliable approach for quantifying the total dietary fiber present in citrus peels. These peels represent a valuable source of both soluble and insoluble fibers, which may confer various health benefits. The enzymatic process employed includes the use of heat-stable α-amylase, followed by digestion with protease and amyloglucosidase to effectively remove protein and starch. Subsequently, the aqueous digest is diluted with four volumes of ethanol to precipitate the soluble dietary fiber. A comprehensive understanding of the components of dietary fiber found in citrus, as well as the estimation process, is essential for enhancing the application of citrus by-products in various fields.