Small Farm to School Act of 2021 This bill directs the Department of Agriculture (USDA) to award three-year grants to eight states or tribal organizations to provide school food authorities with an increased reimbursement for free and reduced price lunches that include at least one component that is comprised entirely of locally-produced and unprocessed foods procured directly from certain agricultural producers. USDA must select at least one state or tribal organization located in each of the following regions: (1) the Mid-Atlantic Region, (2) the Midwest Region, (3) the Mountain Plains Region, (4) the Northeast Region, (5) the Southern Region, (6) the Southwest Region, and (7) the Western Region. USDA must give the highest priority to applications that propose to carry out certain projects, including projects that (1) serve a high proportion of children from socially disadvantaged backgrounds, and (2) increase the availability of locally-produced foods to children. Additionally, priority must be given to states or tribal organizations with a high quantity and variety of growers of local fruits and vegetables on a per capita basis, and with a demonstrated commitment to farm-to-school activities. Each state or tribal organization that receives a grant must provide, from nonfederal sources, an amount equal to 100% of the awarded grant amount.