Villa have announced on their official website that they have secured the services of the goalkeeper from Arsenal.
The 28-year-old Argentine has put pen to paper on a four-year contract with the Villans.
Martinez had been on the books of Arsenal since 2010, but he could not establish himself as the first choice between the posts.
Although the goalkeeper played well for the Gunners in the final weeks of last season due to the injury to Bernd Leno, with the German having now fully recovered, the Argentine has gone back to being a back-up.
Martinez is overjoyed to have move to Villa, and manager Dean Smith is glad to have signed the goalkeeper.
Smith told Villa’s official website: “We are really pleased with the signing of our new goalkeeper Emiliano Martinez. We know how highly Arsenal rated him and we watched his outstanding performances last season in a trophy-winning top side.
“We moved for Emi when we saw the opportunity, as it is rare to be able to buy a top class goalkeeper who hasn’t yet reached their peak age and who can therefore be a key player for our Club for the long term.”
Martinez told Villa’s official website: “When I won the FA Cup and the Community Shield, I told my family that it’s time to have a new challenge.
“He [Dean Smith] explained why he wants me here, the process that he wants from the club and also the playing style, and that’s why I decided to come here.
“Aston Villa gave the opportunity, I trust the process, the playing style and I truly believe that we can have a good season.
“I always decide with my family, I ask for opinions and they all said good things about Villa. I always follow my instincts, and I had no doubts about coming here.”