The agency will be immediately rebranded as Leo Burnett W&K Beijing Advertising Co. and will become part of Leo Burnett Greater China operations.
Guo Weijun, current chairman of W&K Communications, and Wang Yi, managing director, will continue to lead the company.
Both will now report to Michael Wood, chief executive of Leo Burnett Greater China.
The acquisition is part of Publicis Groupe's ongoing plan to strengthen its presence in emerging economies, and follows a series of other recent acquisitions in China, including EmporioAsia in May, CCG in 2007, as well as Betterway Marketing Solutions and Emotion in 2006.
Tom Bernardin, chairman and chief executive of Leo Burnett Worldwide, said: "This is a very important step for our operation in Greater China, especially since it follows Leo Burnett's acquisition of EmporioAsia earlier this year.
"We are thrilled to be making this move with Mr Guo Weijun and Mr Wang Yi of W & K Communications. Together, we will not only increase our market share, but we will create ideas that will connect with people and impact their behaviour in a relevant, interesting and useful way. I anticipate great things from this partnership."
W&K Communications, which was founded in 2004, employs nearly 100 communications specialists and has offices in Beijing and Guangzhou.
The Chinese agency provides services in advertising, promotions, television production and media buying.
Major clients include Air China, Mengniu (Dairy), Yutong (Bus), Holiland (Food), Totole (Condiments) Cofco (Oils and Foodstuffs), Picc (Insurance), Tsingtao Beer and Daliyuan (Food).
Guo Weijun and Wang Yi said: "We've continued to grow at a very steady pace over the past years, and we've reached a point where we need to make the jump from local to global.
"We are very excited about leveraging the resources and international reach of Leo Burnett, and tapping into the wealth of opportunities offered by joining Publicis Groupe. "