Teacher Victims' Family Assistance Act of 2021 This bill establishes the Teacher Victims' Family Trust Fund, from which the Department of Education (ED) must provide financial assistance to certain family members of elementary and secondary school teachers and staff members who are killed by an act of violence while performing their school duties. The bill also increases from 11% to 13% the excise tax on shells and cartridges and provides the trust fund with funding equivalent to the revenues received from the tax increase. Specifically, ED must provide victims' families with (1) funeral assistance; (2) a death benefit payment for the surviving spouse, dependent child, or other next of kin; (3) a monthly living allowance for the surviving spouse until death or remarriage or, if there is no surviving spouse, for each dependent child until age 18; and (4) undergraduate education assistance for each dependent child for five years. Additionally, the bill excludes from a victim's income, for tax purposes, the amount of wages earned in the year of death. It also excludes victims' family assistance received under the bill from gross income for any taxable year.