The Sino-Vietnamese War was primarily driven by the geopolitical tensions between China and Vietnam that escalated after the Vietnamese invasion of Cambodia in December 1978, which led to the toppling of the Khmer Rouge regime. In response, China launched a punitive military strike against Vietnam on February 17, 1979, citing the need to teach Vietnam a lesson for its actions in Cambodia and its treatment of ethnic Chinese in Vietnam. The conflict saw intense fighting, primarily along the Sino-Vietnamese border, where thousands of troops clashed. Chinese leaders believed a swift military intervention would intimidate Vietnam and restore China's influence over Southeast Asia.

The war resulted in heavy casualties on both sides, although estimates vary. China mobilized around 200,000 troops for the invasion, capturing some territory in northern Vietnam, but faced fierce resistance from the Vietnamese military. The conflict lasted until March 16, 1979, when China announced it had achieved its objectives and began a withdrawal, although the conflict caused lasting strains in Sino-Vietnamese relations. This military engagement had significant implications for regional politics, leading to years of tension between the two countries.

The aftermath of the war saw Vietnam solidifying its control over Cambodia, while China re-evaluated its foreign policy in Southeast Asia. These developments contributed to the long-standing rivalry between Vietnam and China, shaping geopolitics in the region for decades to follow.