The Union of Marxists (, SM) is a communist organization in Russia, founded on November 2–3, 2019 by Andrey Rudoy, editor-in-chief of the left-wing magazine Vestnik Buri, YouTube blogger and trade union activist, and Station Marx news resource. The organization considers itself neither Stalinist nor Trotskyist.
The movement participated in the 2021 protests and the 2022 anti-war protests.
In March 2022, a split occurred in the movement, and a part associated with Station Marx organized a new organization "New Reds". New Reds then merged in May 2023 with Marxist Tendency into the Organisation of Communist Internationalists which became the section of International Marxist Tendency in Russia.
In September 2023, the organization was left by its founder Andrey Rudoy. A few weeks later, the Ministry of Justice of Russia recognized him as a foreign agent for his anti-war position.
The organization participates in the labor and environmental movement, organizes feminist-themed events.