Ukrainian President Petro Poroshenko has signed a law declaring December 25 a public holiday.
Poroshenko made the move on November 29, nearly two weeks after Ukrainian lawmakers adopted the legislation officially recognizing the day celebrated by Catholics and Protestants as Christmas Day.
January 7 will remain a public holiday in majority Orthodox Christian Ukraine.
About 9 percent of Ukraine's 42 million population is Catholic or Protestant.
Oleksandr Turchynov, Secretary of Ukraine's Security and Defense Council, described the vote in parliament on November 16 as "historic," saying it would allow Ukrainians to "distance ourselves from Moscow's calendar and Russian imperial standards."
Kyiv and Moscow have been locked in a bitter feud since Russia occupied and illegally annexed Ukraine’s Crimea region in March 2014.
Moscow has also provided political, military, and economic support to separatists who gained control over parts of eastern Ukraine, sparking a war that has killed more than 10,000 people since April 2014.