Monthly Shōnen Magazine (月刊少年マガジン Gekkan Shōnen Magajin?) is a japanese shōnen manga magazine published by Kodansha. Originally, in 1964 it was launched under the name Bessatsu Shōnen Magazine (別冊少年マガジン?). In 1969 it was retitled as Monthly Bessatsu Shōnen Magazine (月刊別冊少年マガジン?) and its publication frequency increased from quarterly to monthly.
