Moritz Rittinghausen (November 10, 1814, in Hückeswagen – December 29, 1890, in Ath, Belgium) was a German advocate and theorist of direct democracy, an early socialist and a politician.
Rittinghausen lived in Belgium temporarily during the period before the March Revolution and emerged there as a leading thinker on social politics.
He took an active part in the German revolutions of 1848–49 as a democrat.
After leaving the country during the Reaction following the Revolution, he later returned to Germany and began to take a role in the labor movement.
He was among the founders of the Social Democratic Workers' Party of Germany, before he was thrown out of the party over political differences.