Ronaldo was favourite for the award having led Real Madrid to their 11th Champions League win last season, scoring the winning penalty in a dramatic shootout against rivals Atletico Madrid.
The former Manchester United star then went on to win a first major international trophy as Portugal were crowed European champions after seeing off hosts France in the final of EURO 2016.
The 31 year-old previously won the award for the 2013-2014 season and he joins Barcelona rival Lionel Messi in winning the honour on a second occasion.
"It's a great honour and thanks to the journalists for voting for me!" Ronaldo said.
"My team-mates are the key - they are the key every year. I work hard myself but without the help of my team-mates this would not be possible.
"Thanks to my team-mates from Real Madrid and Portugal.
"I have to mention Portugal because it was the first in their history. It was different because I've won the Champions League three times. To win something with Portugal was the highlight of my career."
The award, which Messi won last year, is voted for by journalists from UEFA's member nations.
Messi was surprisingly not even placed in the top four this time around, the Argentine ranked fifth behind Barca team-mate Luis Suarez.
Gianluigi Buffon, Toni Kroos, Thomas Muller, Manuel Neuer and Pepe were the other players on the long list.
