The 21-year-old was a bright spot in a difficult campaign for Villa, scoring 12 goals in 38 appearances as Paul Lambert's side scrambled to avoid the drop, while also winning his first caps for the Austria national side.
The new deal keeps Weimann at Villa Park until the end of the 2015/16 season and ends summer speculation over his future.
"I'm really happy that I've signed," he told the club's official website. "I have a feeling of being at home here at Aston Villa.
"I've been here for six seasons now, having started with the Academy in 2006, and last season was tremendous for me and terrific for the team the way we played over the second half of a really demanding campaign.
"On a personal level, I didn't expect at the start of the season that it would go the way it did, with me being involved and starting games almost the whole of the way through.
"It was exciting to be part of the team's development because the potential within this young, exciting team is really strong.
"The last several months of the season we played really well and got better and better as the season went on. Hopefully, we can continue on like we finished and that will be the challenge.
"Like the other young players in the team, I want to keep improving as a player and keep pushing Villa as high as we can in the Premier League.
"I feel like I owe the manager and the club because the manager backed me last season after he came in.
"It's great to be a part of an exciting future at Villa. I'm sure the manager will bring in more new faces to help us and this will make us stronger."