Formelly known as CH-53X, the CH-53K is a general redesign of the CH-53E with new engines, new cockpit layout and a wider cargo hold to allow it to carry a Humvee internally resulting in over twice the lift capacity and radius of action of the previous variant.

Selected by the US Marine Corps in 2006, which has 227 on order, was expected to began flight testing by 2011 but was deferred to 2014

The CH-53K is scheduled to achieve its Initial Operating Capability (IOC) in FY2018