In May 2016, Radunović was called up to the Montenegro national team for a friendly against Turkey.[3] He debuted as a substitute on 14 October 2018, in an UEFA Nations League away match against Lithuania, a 4–1 win.[4]
On 1 September 2021, he scored his first international goal dramatically for his team in 2022 FIFA World Cup qualification against Turkey in 90+7 minute. He entered to game replaced by Zarko Tomasevic on 66th minute and he was a golden substitute for his team to help the Montenegrin escape defeat.