校庆

校慶
xiàoqìng
anniversary of the founding of a school

CEDICT

anniversary of the founding of a school or college

Wiktionary

学校成立纪念日

重編國語辭典

Examples

这次校庆时,他将第一次做主角。

He will play the leading role for the first time in the next school festival.

Source: Tatoeba

Entry Composition