Non-starch polysaccharides (NSPs) are biopolymers included in the fiber of cereal grains and seeds. Among NSPs, arabinoxylans and β-glucans are considered to play the most important role in breadmaking. In the literature to date, there is a lack of studies that summarize the current information on the properties and role of NSPs in this process. This review summarizes the up-to-date knowledge concerning the properties and functionality of the most common cereal NSPs in bread baking. In studies conducted to date, it has been shown that the addition of both arabinoxylans and β-glucans in amounts up to about 6% causes an increase in the water absorption of flour, and as a consequence, it forces the use of a larger addition of water to achieve the desired consistency of the dough. Even a small addition of NSPs can have a positive effect on the dough yield; making more bread from the same amount of flour and such bread is less caloric since neither NSPs nor water contributes to additional calories. Moreover, it has been shown that even a small addition of arabinoxylans or β-glucans has a positive effect on bread volume, moisture, and texture of the bread crumb as well as the preservation of bread freshness. The knowledge concerning cereal NSPs, especially modified ones and of defined structure, is incomplete and further research is needed to characterize their functionality in breadmaking.