Dewey Square Group, a communications company with Boston roots, is becoming part of Hill+Knowlton Strategies of New York as part of a corporate reorganization.

Both firms already have the same corporate parent, WPP of London. But WPP is now putting Dewey Square under the umbrella of Hill+Knowlton, a strategic communications company with global operations.

“We’ll have a much larger platform,” said Chuck Campion, chairman of Dewey Square Group, who said Dewey will retain its management and brand name. The firms have collaborated on some projects.

Dewey Square was founded in Boston in 1993 by three veteran political operatives: Campion, Michael Whouley, and Charles Baker. It was acquired by WPP in 2006. The company, with 90 employees, has eight offices, including in Boston, and is based in Washington, D.C.