The Russian Federation served as a strategic ally of Vietnam for four decades (1950–1990). It was the primary provider of defense aid that assisted Vietnam during the Indochina War and the border conflict with China. Following the collapse of the socialist state in Russia in 1991, the Russian government maintained diplomatic relations with Hanoi, eventually upgrading the relationship to a comprehensive strategic partnership encompassing politics, economics, culture, education, science and technology, and defense and security. This article outlines the defense cooperation between Vietnam and Russia as a crucial pillar of the diplomatic relationship between Hanoi and the Kremlin. It offers a condensed historical overview of Vietnamese-Russian defense collaboration, highlighting the strong historical context of their strategic alliance during the Indochina conflict. The article also focuses on the arms trade and military cooperation agreements between Vietnam and Russia in recent decades, shedding light on the scope and achievements of their defense partnership.