The Korean Peninsula is a peninsula in East Asia. It extends southwards for about 684 miles (1,100 km) from continental Asia into the Pacific Ocean and is surrounded by the Sea of Japan (East Sea) on the east, the East China Sea to the south, and the Yellow Sea to the west, the Korea Strait connecting the first two bodies of water.

Until the end of World War II, Korea was a single political entity whose territory roughly coincided with the Korean Peninsula. Since the cessation of the Korean War in 1953, the northern half has been occupied by North Korea, while the southern half has been occupied by South Korea. "Korean (or Korea) Peninsula", or "Korea", is sometimes used to refer to these two states together, though in South Korea, and in common discourse among many native English speakers, the word "Korea" refers specifically to the South. (This may be due to the perception of North Korea being a taboo subject in and of itself. Also, since North Koreans rarely travel outside of North Korea, the presumption is that any Korean one encounters is from the south).

The northern boundaries for the Korean Peninsula are commonly (and tacitly) taken to coincide with today's political borders between North Korea and her northern neighbors, China (1,416 km along the provinces of Jilin and Liaoning) and Russia (19 km). These borders are formed naturally by the rivers Yalu/Amnok and Tumen/Tuman/Duman. Taking this definition, the Korean Peninsula (including its islands) has an area of 220,847 km².

The peninsula is called Joseon Bando ( ) in North Korea and Han Bando ( ) in South Korea due to the different names for Korea.