His progress at Villa was checked after he ruptured the anterior cruciate ligament in his left knee during a training session in April.
He suffered a set-back after returning against Tottenham on Boxing Day but has played in Villa's last two matches.
Delph came off the bench to fill in at left-back for the
4-1 win over Blackburn
after Nathan Baker was forced off with concussion and continued in the role for Wednesday's
FA Cup defeat by Manchester City.
"I am absolutely delighted. The club has shown great commitment in me by offering me this deal and I was more than happy to sign it," said Delph.
"I want to push on now, improve and play a part as we look to finish the season on a high and build for next season."
Villa manager Gerard Houllier believes that Delph's contract extension shows the strong relationship between club and player.
"We are very confident he will become a very good player for Aston Villa. The fact he signed the contract means he trusts us too," he said.
Source: BBC Sport
Source: BBC Sport