| 10AM Communications | Advertising |
| 141 Premiere Sports & Entertainment | Direct, digital, promotion & relationship marketing; Event/face to face marketing; Sports marketing |
| 1861united | Advertising |
| 24/7 Media | WPP Digital |
| 41?29! | Advertising; Digital |
| 9ine Sports & Entertainment | Sports marketing |
| A.Eicoff | Advertising; Direct, digital, promotion & relationship marketing; Media & production services |
| Acceleration | WPP Digital |
| Actionline | Direct, digital, promotion & relationship marketing |
| Added Value | Consumer Insight |
| Added Value Cheskin | Consumer Insight |
| Addison | Branding & identity |
| Adgistics | Branding & identity ; Technology marketing |
| AdGooroo | Consumer Insight |
| ADK | Advertising |
| AdPeople Worldwide | Advertising; Specialist communications |
| Affectiva | Consumer Insight |
| AGENDA | Direct, digital, promotion & relationship marketing |
| AKQA | Digital |
| all access ltd | Direct, digital, promotion & relationship marketing |
| All Global | Consumer Insight; Healthcare communications |
| All Global Viewing | Consumer Insight; Healthcare communications |
| Alliance | Sports marketing |
| Alpha Salmon | Direct, digital, promotion & relationship marketing; Technology marketing; WPP Digital Partner companies |
| Always ( Shanghai ) Marketing Services Co., Ltd. | Branding & identity ; Entertainment marketing; Event/face to face marketing; Food and beverage marketing; Healthcare communications; Public relations & public affairs |