Valencia has enjoyed an excellent individual season, excelling at right-back for Manchester United.
Manager Jose Mourinho has been effusive in his praise for the Ecuador international this term.
For Wednesday's Europa League final, Valencia was picked by Mourinho to skipper the United team with club captain Wayne Rooney and vice-captain Michael Carrick on the bench.
And the 31-year-old has now been rewarded with a new deal, which includes the option to extend for a further year.
Manchester United stars celebrate Europa League win Fri, May 26, 2017
Click through the gallery for the best snaps of Jesse Lingard and Marcus Rashford enjoying Manchester after their Europa League victory
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Jesse Lingard and Marcus Rashford enjoy a night on the town after Man Utd's win
I am sure that we will be challenging on all fronts next season
Valencia said: "Manchester United has been my life since 2009 and I am absolutely delighted to have signed a new contract. Wednesday evening provided the one trophy this club had never won and it was a true honour for me to captain the team for the final.
"I would like to thank the Manager for the confidence he has given me this season and I am sure that we will be challenging on all fronts next season.
"I would also like to say a big thank you to my family, my team-mates and, of course, the fans, for their amazing support."
Antonio Valencia's deal will keep him at Manchester United until June 2019
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Mourinho added: "It is no secret that I had been an admirer of Antonio’s long before I joined the club. I knew what a fantastic player he was and he has not disappointed me on that front.
"However, what I could never have imagined was what a great person he is.
"I know I have said this before but I truly believe it is a real privilege for us to have such a good player and such a good man. I am delighted he has extended his contract."