This chapter provides a short introduction to those movements that have been commonly identified most famous left-wing terrorist groups, as well as the features that researchers have claimed are typical for such groups. Left-wing terrorism is most strongly associated with the revolutionary movements that operated in several countries from the 1960s until the 1980s. Typologies of terrorism based on political motivation have perhaps been attractive due to their apparent simplicity: the most visible part of terrorism campaigns has often been the political objectives. Ideologies and political objectives that inspire terrorist campaigns tend to reflect the zeitgeist. Therefore, the left-wing terrorist campaigns have been most common in times when left-wing ideologies have been en vogue. The period from the 1960s until the early 1990s is indeed one period which witnessed a multitude of political and social activities inspired by left-wing ideologies – including campaigns in which terrorist tactics were used.