Commission Junction is an online advertising company owned by ValueClick.Commission Junction is the largest affiliate network in North America, powering 62% of the top 500 web retailers affiliate marketing programs and operates worldwide. Along with being the world's largest Affiliate Network, Commission Junction also promotes their Search Marketing services and their media services. Their corporate headquarters is located in Santa Barbara, California, with other offices in Chicago, New York, San Francisco, Westborough and Westlake. Commission Junction has also offices in the UK, Germany, France, Sweden and Spain.

Commission Junction has over 1,500 customers including Overstock.com, Buy.com, Home Depot, Circuit City, and Yahoo!.