Turner, 22, averaged 12.7 points, 6.4 rebounds, 1.8 blocks and 1.3 assists per game last season for the Pacers. He was the No. 11 overall pick in the 2015 NBA Draft out of the University of Texas.
"I'd like to thank the Simon family and the Pacers organization for giving me this opportunity," Turner said in a release from the Pacers. "It took a lot of hard work to get here and I didn't do it on my own; I'd like to thank my family, as well as my teammates, past and present, and the coaching staff for helping me get to this point. I'm excited to build here in Indiana and I'm looking forward to the future."
Turner has the longest tenure with the Pacers out of all the players on the team's roster.
"Myles has been great here, not only on the court; but he represents this organization unbelievably off the court as well," Pacers president of basketball operations Kevin Pritchard said.
"His hard work and dedication to both his game and to our franchise exemplify what it means to be a Pacer. We're thrilled to have him here long term."
The Pacers host the Memphis Grizzlies at 7 p.m. on Wednesday at Bankers Life Fieldhouse in Indianapolis.