He started the season making five solo tackles in a 19–31 loss to the Denver Broncos. During a Week 6 contest against the Tennessee Titans, he made six total tackles and intercepted Titans quarterback Matt Hasselbeck for his first pick of the season. On November 25, 2016, Timmons racked up ten combined tackles and intercepted Brandon Weeden and scored a 52-yard touchdown for the first of his career. The Steelers went on to lose to the Browns 14–20. During Week 14, he made a season-high 11 solo tackles in a loss to the San Diego Chargers. He finished his sixth NFL season with a total of 106 tackles, 6.0 sacks, 2 forced fumbles and a career-high 3 interceptions. This was his first season starting all 16 regular season contests.
The Pittsburgh Steelers finished the season 10–6 and received a playoff berth. On January 9, 2016, Timmons recorded four combined tackles in an 18–16 AFC Wildcard victory over the Cincinnati Bengals. On January 17, 2016, he made six combined tackles in a 23–16 divisional loss to the eventual Super Bowl champions, the Denver Broncos.
On October 20, 2016, the Steelers lost to the New England Patriots and Timmons racked up a season-high 11 solo tackles during the game. In Week 11, Timmons recorded eight combined tackles and made his first sack of the season in a 24–9 victory over the Cleveland Browns. During Week 13, he made seven combined tackles and intercepted New York Giant's quarterback Eli Manning and returned it 58-yards. He finished the season with 114 combined tackles, 2.5 sacks, 5 pass deflections, two interceptions, and a forced fumble in 16 games and 16 starts.