The 1950s (pronounced nineteen-fifties; commonly abbreviated as the "Fifties" or the "'50s") (among other variants) was a decade that began on January 1, 1950, and ended on December 31, 1959.

Throughout the decade, the world continued its recovery from World War II, aided by the post-World War II economic expansion. The period also saw great population growth with increased birth rates and the emergence of the baby boomer generation. Despite this recovery, the Cold War developed from its modest beginnings in the late 1940s to a heated competition between the Soviet Union and the United States by the early 1960s. The ideological clash between communism and capitalism dominated the decade, especially in the Northern Hemisphere, with conflicts including the Korean War in the early 1950s, the Cuban Revolution, the beginning of the Vietnam War in French Indochina, and the beginning of the Space Race with the launch of Sputnik 1 in 1957. Along with increased testing of nuclear weapons (such as RDS-37 and Upshot–Knothole), the tense geopolitical situation created a politically conservative climate. In the United States, a wave of anti-communist sentiment known as the Second Red Scare resulted in Congressional hearings by both houses in Congress. The beginning of decolonization in Africa and Asia also took place in this decade and accelerated in the following decade. During the 1950s, the world population increased from 2.5 to 3.0 billion, with approximately 1 billion births and 500 million deaths.