As well as being the official betting partner, the deal will see William Hill named as the sponsor of three races held at the Aintree racetrack during the Grand National.
The festival runs from 13-15 April.
The three races are the Grade 1 William Hill Aintree Hurdle on 13 April, the William Hill Handicap Hurdle on 14 April and the Grade 3 William Hill Handicap Chase on 15 April.
Daryl West, William Hill’s head of sponsorship, social and PR said the company was “delighted” to be involved as the event’s official betting partner for the next three years.
“The Grand National Festival at Aintree is one of the pinnacles of the National Hunt calendar and we are delighted to be involved as the official betting partner for the next three years,” he said.
“Horseracing is a vital part of our heritage, and it was an easy decision for us to support not just the biggest race in the sport but a huge event in the annual sporting calendar.”
William Hill also announced that it would be agreeing to non-runner, money-back terms from 9am today (20 February), meaning that a bet will be refunded into the betting customer’s account if the horse they wagered on does not end up competing in the race.
“William Hill is synonymous with horse racing in this country so we are thrilled they are going to be involved with our flagship meeting at Aintree for the next three years,” said Dickon White, Aintree and North West regional director at The Jockey Club.
In January, 888 William Hill, a subsidiary of 888 Holdings subsidiary, announced that Phil Walker would be taking over as the company’s managing director of UK and Ireland operations, having previously served as UK managing director for William Hill.
Previously to William Hill, Walker had worked as group chief operating officer for the Gibraltar stock exchange.