Oxlade-Chamberlain becomes Wenger's third summer signing following the arrivals of defender
from League One side Charlton and striker
from French club Lille.
"We are delighted that Alex has decided to join us," Wenger stated. "He is an exciting young player who will provide us with creativity and offensive quality.
"Alex is a versatile player who can play in a number of positions. He can play as an attacking centre midfielder, or wide left and right.
"He is a perceptive passer of the ball, has a great understanding of the game and looks to be a very good team player."
Oxlade-Chamberlain, who turns 18 on 15 August, commented: "I'm so excited to be joining Arsenal. It's a fantastic club and I'm really looking forward to playing football at the highest level.
DID YOU KNOW...?
Alex Oxlade-Chamberlain is the son of Mark Chamberlain - the former Sheffield Wednesday, Stoke and Portsmouth winger who won eight caps for England
"Arsenal have a great manager in Arsene Wenger, top quality players and an attractive style of play. These were all important factors in me choosing to sign for Arsenal.
"I'm proud to be joining Arsenal, but I would also like to take this opportunity to thank everyone at Southampton for their help and support during the early part of my career, for which I will always be grateful.
"I'm now looking forward to meeting all my new team-mates and giving absolutely everything in an Arsenal shirt."
Oxlade-Chamberlain made his Southampton debut as a 16-year-old in March 2010 and signed a three-year contract in August of that year.
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