The High Treason Incident was a socialist-anarchist plot to assassinate the Japanese Emperor Meiji in 1910, leading to a mass arrest of leftists, and the execution of 12 alleged conspirators in 1911.

The High Treason Incident created a shift in the intellectual environment of the late Meiji period towards more control and heightened repression for ideologies deemed potentially subversive. It is often cited as one of the factors leading to the promulgation of the Peace Preservation Laws.