Jones, 24, was a second-round pick of the Falcons in 2016. He was scheduled to become a free agent after the 2019 season.
Jones is the second Falcons player to sign a new contract this week. Defensive tackle Grady Jarrett agreed to a four-year extension Monday.
Jones has quickly become one of the NFL's most prolific linebackers. The former LSU standout has recorded 297 tackles, 15 tackles for loss and eight interceptions since entering the league.
Jones recorded 53 tackles in six games last season. He suffered a foot injury in the Falcons' Sept. 6 season opener against the Philadelphia Eagles and returned in early December.
Jones was a Pro Bowl selection in 2017.