The 31-year-old specialist climber joins from Movistar, after six years with the team formerly known as Caisse d'Epargne during which he claimed a stage victory at the 2010 Vuelta a Espana.
A dedicated team player, or 'domestique', Lopez is relishing his role within the British-based squad.
He said: "I am very happy to have signed for Team Sky.
"As soon as Team Sky approached me, there was nobody else I wanted to sign for and I want to work as hard as I can to gain success for the team.
"Most of the time that will be for someone else, but if the chance arises for me as well, then I will definitely try to take it. The most important thing though, is that everyone is happy with my work."
Team Sky on Thursday announced the arrival of Italian rider Dario Cataldo, also on a two-year contract, and last week brought in experienced Norwegian Gabriel Rasch.