The attacking midfielder has been one of the stand-out performers in Serie A this season and had been linked with a big-money summer switch.
The likes of Barcelona and Manchester United were rumoured suitors of the 24-year-old, but he has now put the prospect of a summer move to bed with his signing of a new long-term deal.
"I have never thought about leaving Roma," Pjanic told Sky Italia.
"It's true that negotiations have been long, but also because this has been an important season.
"I wanted to keep my concentration, without talking about the contract. But the club knew my will. We have found an agreement and I'm happy.
"There have been offers from other clubs, but I prefer not saying who. I've always thought my future was here.
"Rudi Garcia [Roma coach] counts on me a lot. I think I have made the right choice."