The New Year Honours list recognises the achievements and service of extraordinary people across the United Kingdom, with sports people honoured alongside those from the arts and sciences, charitable and welfare organisations, public service and community volunteers.
Thomas had already been awarded an MBE (Member of the Most Excellent Order of the British Empire) in 2009 for his success on the track at the Olympics as part of the Great Britain team. He was awarded an OBE (The Most Excellent Order of the British Empire) after becoming the first Welshman and only the third Briton to win the Tour de France. Thomas receives an OBE for services to cycling.
His Tour de France victory was the sixth time in seven years that a British rider won the sport's biggest race, having previously supported teammates Chris Froome and Bradley Wiggins in their victories. Wiggins was awarded a knighthood after he won the Tour de France and a gold medal in the 2012 London Olympics. Team Sky manager Dave Brailsford was also given a knighthood for services to cycling.
News of the award was given on Friday evening and confirmed by Thomas’ Team Sky squad.
"This is an amazing honour," Thomas said via Team Sky. "2018 will always be a year I remember for everything I achieved around both the Dauphine and especially the Tour.
"This is the icing on the cake and I am so grateful to everyone who played a part in helping me get recognised once again."
“I’m really looking forward to seeing what 2019 has in store, as we look to create more history as a team."
In December Thomas was voted BBC Sports Personality of the Year 2018 having also been named BBC Cymru Wales Sports Personality of the Year 2018.
Team Sky has still to confirm its Grand Tour leaders but Thomas is expected to return to the Tour de France and target overall victory alongside Chris Froome, while Egan Bernal targets the Giro d’Italia.