Oris will have an extended range of branding on the team's cars, drivers' gloves and overalls, as well as visibility on the pit wall canopy and other elements of the team's trackside environment.
Oris has been a partner of the Williams team since 2003 and during this time has created several bespoke drivers' watches, the most recent being the Nico Rosberg Limited Edition chronograph.
To celebrate both the contract extension and Williams' 30th anniversary in 2008, Oris is launching a premium limited edition watch, the jubilee edition Oris TT3 Formula Gold, with only 300 numbered units being released for sale worldwide.
Ulrich Herzog, chairman and CEO of Oris, Switzerland, said: "This new three-year commitment which takes us through to the end of 2010 is a sign of our desire to continue to derive more from our association with the team as Oris strengthens its brand, reputation, sales and international appeal."
Sir Frank Williams, team principal of AT&T Williams, said: "In a split-second business, having a watchmaker of Oris' stature and pedigree with us through to 2010 is a great vote of confidence."