No. 3 Middle School or No. 3 High School may refer to any of these secondary schools:

China

Fuzhou No.3 Middle School, in Fuzhou, Fujian Zhuhai No.3 High School, in Zhuhai, Guangdong Nanning No.3 High School, in Nanning, Guangxi Harbin No 3 High School, in Harbin, Heilongjiang Nanjing No. 3 High School, in Nanjing, Jiangsu Tieling No.3 Middle School, in Tieling, Liaoning Shandong Province Zaozhuang No. 3 High School, in Zaozhuang, Shandong Tianjin No. 3 High School, in Tianjin

Iran Allameh Helli No.3 High School, in Tehran Hadaf No.3 High School, in Tehran

See also No. 1 Middle School (disambiguation) No. 2 Middle School (disambiguation)