The club made the announcement prior to their Premier League clash with Watford on Friday evening as the side go in search of a record points tally this campaign.
"This contract is very important for me and my family. I am very happy here – this is the best club for me," said Mirallas in a statement.
"I've been here five years and it's very important for me to win a trophy here. I've said before that my dream is to win at least one trophy with Everton and I firmly believe we are heading in the right direction.
"We have an amazing manager, an amazing team, and amazing fans. This is an exciting time for the club. I hope we sign some top players to fight for the Champions League places next season."
Mirallas has made 171 appearances for Everton, having joined from Greek side Olympiacos in August 2012.