Professional services networks are networks of independent firms who come together to cost-effectively provide professional services to clients through an organized framework. They are principally found in law and accounting. They may also be found in investment banking, insurance, real estate and architectural services. Any profession that operates locally, but has clients in multiple locations, are potential members of a network. This entry focuses on accounting, legal, multidisciplinary and specialty practice networks. Today members of these networks employ more than one million professionals and staff and have cumulative annual revenues that exceed $200 billion.

The accounting networks and associations developed first to meet the requirement of the SEC of public company audits. They include the well-known accounting networks like PwC, Deloitte, Ernst & Young and KPMG  (also known as the Big 4 Audit Firms) as well as more than 30 other accounting networks and associations. They are highly structured entities.The law firm network developed in the late 1980s. They include legal and law firm based multidisciplinary networks like Lex Mundi, World Services Group, TerraLex, Meritas, and the State Capital Group.

There are more than 175 known networks in law, 40 in accounting, and 20 specialty networks. Individual networks have revenues exceeding $20 billion.