Grant Thornton International is a global organisation of accounting and consulting member firms which provide assurance, tax and specialist advisory services (SAS) to privately held businesses, public interest entities, and public sector entities. Grant Thornton International is a not-for-profit, non-practising, international umbrella membership entity organised as a private company limited by guarantee. Grant Thornton is incorporated in England and Wales, and has no share capital.

Member firms within the global organisation operate in over 100 countries. Member firm fee income rose by 14% in 2008 to US$4 billion. There are over 2,600 member firm partners and total personnel of over 30,000, including partners.

Although many of the firms now carry the Grant Thornton name, they are not all members of one international partnership. Each member firm is a separate national entity, and governs itself and manages its administrative matters independently on a local basis.