The 20-year-old was one of five homegrown youngsters to commit their long-term futures to the Gunners in December.
Jenkinson has admitted that the feeling of being part of a group of exciting young players in North London made signing his contract more special.
He told the club's official website: "In all honesty, to look down the table at the sort of players who are signing with me shows the direction this club is moving in, we are going forwards.
"To have players like Aaron, Jack, Kieran and Alex with me, they are all top-class players and still young.
"I think it is fantastic we have all signed, hopefully we all have big futures and more importantly can bring success to the club. That has to be our aim."
Jenkinson has made 16 appearances for Arsene Wenger's side this season and also earned his first England cap against Sweden last November.