The attacking midfielder has come through the ranks at Boca and made his debut for the first team this season.
Suarez also formed part of the Argentina team that won the South American Under-17 Football Championship last year and will link up with the La Liga club in February.
The 18-year-old is to feature for his nation's under-20 side at the South American Youth Football Championship early next year before joining up with Villarreal's B team.
However, Suarez, who was also linked with a move to Valencia, hopes to eventually earn a first-team berth at El Madrigal.
"I'm very happy to have signed for Villarreal and I only want to bring joy to the fans," he told the club's official website.
"I always wanted to play in Spain and now I'm going to, so I’m very happy.
"I consider myself a forward or an attacking midfielder and I like to score and get involved. I'll try to show in the B team what I can do in the future in the first team.
"The B team is a very good team with a fantastic group of players. I'm joining a team that treats the ball very well and it's a good opportunity."
