The 25-year-old midfielder moved to Villa Park from Crewe in 2012 and has gone on to establish himself in the first-team picture.
And having played all of Saturday's opening day win at Bournemouth, Westwood has now committed himself to Villa for the foreseeable future.
"I am extremely pleased to sign a new contract and commit my future to Aston Villa," he told the club's official website.
"I was made to feel very welcome from the moment I first walked through the door and I'm very happy at the club.
"I believe I'm now entering what I hope will be the peak years of my career and I look forward to spending them here."
Tim Sherwood's side welcome Manchester United to Villa Park on Friday night, with the winners guaranteed to top the Premier League table heading into the remaining weekend fixtures.
Source : PA
Source: PA