Donlen LLC is an American fleet leasing and management company headquartered in Bannockburn, Illinois, a suburb of Chicago.

With offices throughout the U.S. and Canada, the company provides consultation, maintenance, and outsourcing for corporate vehicle fleets.

In September 2011 the company was acquired by Hertz Global Holdings, Inc for $250 million in cash and the assumption of $770 million in Donlen fleet debt and operated as a subsidiary of the Hertz Corporation.

Donlen partnered with the EDF in a strategic alliance to enable commercial and municipal vehicle fleets to monitor and reduce their carbon emissions.

[4] In addition, Donlen partnered with the EPA's SmartWay Program to display Smartway Vehicle Certifications on qualifying vehicles to help drivers and fleet managers choose the best performers.