The 21-year-old Ulster player scored a Six Nations record seven tries as Ireland secured their first Grand Slam since 2009.
Tournament organisers announced that Stockdale took 32 per cent of the public vote, well clear of his team-mate Conor Murray in second, while fellow Ireland players Johnny Sexton and Keith Earls finished third and fourth, respectively.
“It has been a truly memorable few weeks, making my first NatWest 6 Nations appearance, winning the championship and then going on to complete the Grand Slam against England,” Stockdale said, in a statement released by the Six Nations.
“Breaking the try-scoring record was the cherry on top!
“It’s an absolute honour to win the NatWest player of the championship, especially when you look at the amazing calibre of those short-listed.”
The previous record of six tries in one Six Nations campaign was jointly held by Shane Williams, Chris Ashton and Will Greenwood.
More than 78,000 votes were cast on a six-player short-list, with Italy full-back Matteo Minozzi taking fifth and France captain Guilhem Guirado sixth.
Stockdale, who only made his Test debut last summer, claimed try doubles in Ireland’s victories over Italy, Wales and Scotland, then added another touchdown during the Grand Slam-clinching triumph against England at Twickenham on March 17.
Stockdale joins previous Irish winners Brian O’Driscoll, who won it a record three times, Paul O’Connell, Tommy Bowe and Gordon D’Arcy.
Prior to Stockdale, the award was won for two years in succession by Scotland full-back Stuart Hogg.
And the winner is…!!
— NatWest 6 Nations (@SixNationsRugby) March 23, 2018
Know more about Sport360 Application