The advertising industry is the global industry of public relations and marketing companies, media services, and advertising agencies. Several large advertising agencies, including WPP plc, Omnicom, Publicis Groupe, Interpublic and Dentsu, are among the industry's largest. It is a global, multibillion-dollar business that connects manufacturers and consumers.^[1] The industry ranges from nonprofit organizations to Fortune 500 companies.

In the United States, there are more than 65,000 advertising agencies employing nearly 250,000 employees with annual revenues of $166.8 billion as of 2014.^[1] In 2016, global advertising sales reached $493 billion.^[2] For 2017 it was estimated that digital ad sales were first to surpass the TV market.^[2]

Trade associations representing parts or all of the advertising industry include:

• Advertising Association, a London-based trade association representing United Kingdom-based advertising agencies
• American Advertising Federation, a Washington, D.C.-based trade association representing U.S.-based agencies
• Association of National Advertisers, a New York City-based association representing U.S. marketing agencies and companies
• International Advertising Association (IAA)^[3]

• AdChoices
• Google Ads
• Microsoft Advertising