Sejong A () is a constituency of the National Assembly of South Korea. The constituency consists of the southern portion of Sejong City. As of 2024, 171,472 eligible voters were registered in the constituency.
Sejong A was created ahead of the 2020 South Korean legislative election from the former Sejong constituency as a result of an increase in the area's voter population.
Sejong A is generally viewed as a Democratic Party stronghold as the area consistently voted for the candidates affiliated with the Democratic Party in previous elections.
The constituency consists of the more urban neighborhoods of Hansol-dong, Saerom-dong, Dodam-dong, Sodam-dong, Boram-dong, Daepyeong-dong, Dajeong-dong, and the townships of Bugang-myeon, Geumnam-myeon, and Janggun-myeon.