Korean New Year, commonly known as SeolNal (Hangul: 설날; RR: Seollal; MR: Sŏllal), is the first day of the lunar calendar. It is the most important of the traditional Korean holidays. It consists of a period of celebrations, starting on New Year's Day. Koreans also celebrate solar New Year's Day on January 1 each year, following the Gregorian Calendar. The Korean New Year holiday lasts three days, and is considered a more important holiday than the solar New Year's Day.

The term "Seollal" generally refers to Eumnyeok Seollal (음력 설날, lunar new year), also known as Gujeong (Hangul: 구정; Hanja: 舊正). Less commonly, "Seollal" also refers to Yangnyeok Seollal (양력 설날, solar new year), also known as Sinjeong (Hangul: 신정; Hanja: 新正).

Korean New Year generally falls on the day of the second new moon after winter solstice, unless there is a very rare intercalary eleventh or twelfth month in the lead-up to the New Year. In such a case, the New Year falls on the day of the third new moon after the solstice (next occurrence will be 2033).