The two Canberra-class ships will be the largest vessels constructed for the Royal Australian Navy, displacing more than 30,000 tons.
The Capability Support Coordinator services contract is for a period of five years and carries a value of more than $48 million, the Department of Defense said.
"KBR will bring their world-class asset management expertise to the sustainment of Australia's new LHDs," said Minister for Defense David Johnston. "This will ensure the vessels are always ready to meet their operational commitments, and maximizes the availability of the ships throughout their 40-year lives."
The contract contains a mixture of fixed and tasked services.
The first LHD, the Canberra, began in 2008 and is scheduled to begin sea trials this year. Construction of the Adelaide began in 2010.
Additional details of the contract with Kellogg, Brown & Root Pty Ltd were not disclosed.