Duty After School (Korean: 방과 후 전쟁활동) is a 2023 South Korean military sci-fi thriller dystopian teen drama television series created by Lee Nam-gyu, written by Yoon Soo and directed by Sung Yong-il. The series stars an ensemble cast including Shin Hyun-soo, Lee Soon-won, Im Se-mi, Kwon Eun-bin, Kim Ki-hae, Kim Min-chul, Kim So-hee, Kim Su-gyeom, Kim Jung-lan, Moon Sang-min, Shin Myung-sung, Shin Su-hyun, Shin Hye-ji, Ahn Da-eun, Ahn Do-gyu, Yeo Joo-ha, Oh Se-eun, Woo Min-gyu, Yoon Jong-bin, Lee Yeon, Ji Min-hyuk, Choi Moon-hee, Hong Sa-bin, and Hwang Se-in. Based on the webtoon of the same name by Ha Il-kwon, which was later serialized on Naver Webtoon, it is about "purple objects" that appear in the skies around the world and attack humans, so students become cadets to fight against the strange creatures. It was released from March 31 to April 21, 2023, on TVING's Fridays at 16:00 (KST). It is also available for streaming on Viu and Viki in selected regions.

The series was divided into two parts: Part 1 was released on March 31, 2023, while Part 2 on April 21, 2023.