Korean mixed script () is a form of writing the Korean language that uses a mixture of the Korean alphabet or Hangul () and Hanja (, ), the Korean name for Chinese characters. The distribution on how to write words usually follows that all native Korean words, including suffixes, particles, and honorific markers are generally written in hangul and never in hanja. Sino-Korean vocabulary or hanja-eo (), either words borrowed from Chinese or created from Sino-Korean roots, were generally always written in hanja, although very rare or complex characters were often substituted with hangul. Although the Korean alphabet was introduced and taught to people beginning in 1446, most literature until the early twentieth century was written in literary Chinese known as hanmun ().
Although examples of mixed-script writing are as old as hangul itself, the mixing of hangul and hanja together in sentences became the official writing system of the Korean language at the end of the nineteenth century, when reforms ended the primacy of literary Chinese in literature, science, and government. This style of writing, in competition with hangul-only writing, continued as the formal written version of Korean for most of the twentieth century. The script slowly gave way to hangul-only usage in North Korea by 1949, while it continues in South Korea to a limited extent. However, with the decrease in hanja education, the number of hanja in use has slowly dwindled, and in the twenty-first century, very few hanja are used at all. In Yanbian Korean Autonomous Prefecture in China, the local newspaper Northeast Korean People's Daily published the "workers and peasants version" which used all-hangul in text, in addition to the existing "cadre version" that had mixed script, for the convenience of grassroots Korean people. Starting April 20, 1952, the newspaper abolished the "cadre version" and published in hangul only, soon the entire publishing industry adopted the hangul-only style.
The development of hanja-honyong required two major developments in orthographic traditions of the Korean Peninsula.