Gaultier will oversee the spring-summer 2011 collection to be revealed in 2010, and Lemaire will take over for the fall-winter 2011 collection, the Paris-based firm said in a statement.
The move puts an end to "seven fruitful years of creative partnership" and allows Gaultier "to concentrate on his own projects," the statement said.
Much tamer and preppy than his own signature line, Gaultier's collections for Hermes consistently garnered critical acclaim.
"This has been a marvelous adventure which has allowed me to learn about a new 'savoir faire,"' said Gaultier. He said he'd maintain "a privileged relationship" with Hermes, which has a 45 percent stake in his own company, Jean-Paul Gaultier.
His departure comes three weeks after the death of Hermes' former manager Jean-Louis Dumas, who had been influential in attracting artists to revive his brand's design and identity.
A prominent avant-garde figure on the Paris fashion scene, Gaultier is largely credited with reinventing Hermes women's ready-to-wear collection.
Hermes got its start in 1837 as a saddlemaker and its biggest cash cows remain its leather handbags and accessories divisions.
