Also known as Orthodox New Year, the oxymoronic Old New Year is a traditional holiday celebrating the start of the new year on the Julian calendar. Celebrations begin the evening of 13 January on the more widely observed Gregorian calendar, just like New Year's Eve, and the new year begins 14 January on the Julian calendar. The Old New Year tradition is found primarily in Russia as well as Serbia, Macedoni Montenegro, Georgia, Belarus, Kazakhastan, Azerbaijan, Ukraine, Bosnia and Herzegovina, Uzbekistan, Moldova, Wales and Switzerland.

In Scotland, some Gaelic communities such as South Uist, Eriskay, Glenfinnan and Burghead in Morayshire celebrate Old New Year on 12 January.