The three-year contract covers all direct and online communications across the Asia-Pacific region.
The online task includes digital strategy and mobile marketing, digital media planning and buying, which will be handled by Neo@Ogilvy, and search marketing.
Annette King, OgilvyOne London's deputy managing director, said: "Creatively and strategically, it will present us with some exciting challenges. Asia and the Pacific is a rapidly developing market, and you have a uniquely complex set of brand communications issues to solve."
Daniel Lloyd, BA's marketing communications manager for Asia and the Pacific, said: "OgilvyOne demonstrated a real passion for the British Airways brand and presented us with excellent strategic and creative ideas."