Joseph Leinen (born 6 April 1948) is a German politician who served as Member of the European Parliament (MEP) from 1999 until 2019.

He obtained a law degree in Germany in 1972 and a Certificate of Advanced European Studies from the College of Europe in Bruges, Belgium, in 1974.

He received the nickname "container-Jo" during a demonstration, having climbed a container in order to coordinate protest actions by megaphone.

[1] Because of his participation at a demonstration against the Brokdorf Nuclear Power Plant (1981), he was briefly charged with being "guide and ringleader" of a rioting 'mob', however the Federal Constitutional Court eventually dropped charges against him, ruling that there can not be a case of "guide and ringleader" during collective actions.

In the negotiations to form a coalition government under the leadership of Chancellor Angela Merkel following the 2017 federal elections, he was part of the working group on European policy, led by Peter Altmaier, Alexander Dobrindt and Achim Post.