It is a four-year, $58 million contract, according to the Houston Chronicle, with $23.5 million guaranteed.
Cunningham's $14.5 million average annual salary makes him the NFL's third-highest-paid inside linebacker, behind the Seahawks' Bobby Wagner and the Jets' C.J. Mosley.
Cunningham, 25, a second-round pick of the Texans in 2017, has started since arriving in Houston next to Benardrick McKinney, creating one of the NFL's most consistent inside linebacker duos. Cunningham has especially thrived against the run with the Texans. According to Pro Football Focus, he led all linebackers with a 14.2 run-stop percentage in 2019.
Cunningham has missed just two games in his three seasons with the Texans.
"Zach Cunningham is a guy who day in and day out just gets the job done and makes plays that always leave you shaking your head a little bit," defensive coordinator Anthony Weaver said. "You're like, 'how did he make that play?'"
Earlier in training camp, head coach and general manager Bill O'Brien said he wanted Cunningham to be in a Texans uniform "for a long time."
"He's very athletic, very instinctive, a really good tackler," O'Brien said. "He's made a couple of plays on screen passes where he's fended off the blocker and been able to push the ball carrier back inside where to where his help is coming from. He can play zone coverage. He can play man coverage. He's a good blitzer. We can use him in a lot of different areas -- not just at inside backer. He can do a lot of different things for us. He's a really, really good football player."