Sneyd, who has kicked two match-winning golden point drop-goals this season, was Hull’s player of the year in 2016.
He was man of the match in Hull’s Challenge Cup final victory that year and repeated the feat when the black and whites returned to Wembley the following season.
“It’s a massive weight off my shoulders and now I can fully concentrate on playing my rugby for Hull rather than worrying about my future,” said Sneyd of his new deal.
“The rugby is going really well at the moment and my family is really settled here in Hull, so there was never any reason for us to move away.”
He added: “I am really looking forward to just cracking on in the next few years and hopefully we get the chance to win a few more trophies.
“I’m really happy at the club, it is a good place to be; it is a good setup and I think we are going places. The future looks very promising for us.”
Oldham-born Sneyd, 28, began his career with Salford in 2010 and joined Hull five years later, after spending a season on loan with Castleford Tigers.
He has made 115 appearances for Hull, kicking 408 goals and 24 one-pointers, including the sudden-death winner away to Catalans Dragons last Saturday.
Hull coach Lee Radford said: “When I took over as head coach of the club there were a lot of games we lost by four or six points.
“Marc Sneyd’s goal kicking ability means we don’t find ourselves in that situation as often.
“I still think that Marc’s best years are ahead of him despite the fact that he has already brought two Challenge Cup trophies home for us.
“He is the sort of player who steps up to the plate when the pressure is on. We want him to be rolling out in some more cup finals over the next three years.
“I’m really pleased to see Marc staying with the club and I’m sure the fans will be too.”