Alan Leaman is leaving this summer to join the Management Consultancies Association as chief executive.
Leaman, a former director of strategy for the Liberal Democrats, joined the ABI in 2001 from Hill & Knowlton.
ABI director general Stephen Haddrill said: 'I thank Alan for the excellent contribution he has made to the ABI's success over the past seven years.'
The ABI has nearly 400 member companies. It represents them to the Government, and to the regulatory and other agencies, and is an influential voice on public policy and financial issues.