In September 2014 Team Sky announced that Poels would join them from 1 January 2015. His first win for the team came in the 2015 Tirreno–Adriatico, where he led the team following the withdrawal of Chris Froome. Poels won stage 4 into Castelraimondo with an attack on the final climb and a solo descent to the finish line. He moved into the lead of the race and went on to finish seventh in the overall standings. He later finished second overall at the Tour of Britain, winning the toughest mountain stage with an uphill finish on Hartside Fell.