Jenkinson, who joined the club in June 2011 after making just nine appearances for Charlton, has been rewarded for his fine form this term with a new improved contract.
The 20-year-old made 14 appearances in all competitions last season, but he has impressed this campaign after filling in for the injured Bacary Sagna in the opening weeks of the season.
Gunners boss Arsene Wenger has seen enough to reward the full-back with a contract extension as he looks to secure his best young players on long-term deals.
Jenkinson's performances have earned a call-up to the England squad and he could make his debut in Wednesday's friendly with Sweden.
Arsenal are expected to confirm the news of Jenkinson's new deal later this week and the news will be a boost ahead of this weekend's North London derby with Tottenham.