The clubs have secured a 10-year contract with Emerald Group, a Bingley-based publishing group, which will take effect from November 1.
Although the exact finances are not being disclosed, the money will help towards a new shared main stand at Headingley that forms the major part of a £40m stadium upgrade.
Yorkshire and Leeds Rhinos are renting the main stand over a period of 42 years after Leeds City Council brokered a deal with a London-based blue-chip financial institution to provide the cash, with contracts set to be signed next month.
Leeds Rhinos are also building a new south stand on the rugby ground, with the existing structure to be demolished in August.
Work on a new south stand will begin in September, when the existing shared main stand will also be demolished.
The new main stand, which will be completed in 2019 and known as the Emerald Stand, will help to keep international cricket in Leeds and the city at the forefront of international rugby.
Mark Arthur, the Yorkshire chief executive, said: “We are very excited to enter into partnership with Emerald Group, who have just celebrated 50 years since being founded in Bradford in 1967.
“This is a unique joint venture between the club, the Rhinos and Emerald and underpins the development of the North-South stand (main stand).
“We’ve got a very good relationship with the Emerald Group through its charitable foundation, which has always been very supportive, and to get a local Yorkshire company to support Headingley in this way is fantastic. The name ‘Emerald’ is very tasteful, I think, and a really good name for the stadium.”
Emerald Group will enjoy a range of commercial, community and charitable benefits as part of the deal, while a 450-seater banqueting suite in the new stand will also be known as the Emerald Suite.
The adjoining cricket and rugby grounds will also be independently named using the new backer’s name.
Gary Hetherington, Leeds Rhinos chief executive said: “We are delighted to have worked alongside our partners at Yorkshire CCC to complete this new arrangement.
“This sponsorship is another vital step in our vision to transform our home once again into an iconic sporting venue with the exciting redevelopment plans set to begin in late summer.
“We are proud to have been associated with Emerald for many years through their charitable foundation’s support of our own Leeds Rhinos Foundation, which uses the power of sport to change lives, and this new partnership strengthens the bond between the two organisations.”
This fillip to Yorkshire and Leeds Rhinos comes after years of hard work on the stadium redevelopment. Dr Keith Howard, chairman of the Emerald Group, said his group was only too happy to support them in such a key way.
“As a business founded in Yorkshire, it’s important that we support our local community. So it’s fitting that we’re working with Headingley Stadium to continue to host world-class sport.”