The Assistant Chief of the Naval Staff (Capability) is a senior Royal Navy appointment responsible he is accountable for planning and delivering the larger part of future maritime effectiveness; he does this on behalf of the First Sea Lord.

[1] The post was created in 2013 the office holder currently chairs the maritime capability board which is accountable for planning and delivering the larger part of future maritime effectiveness he does this on behalf of the First Sea Lord and Chief of Naval Staff.

In addition, he liaises with the Finance Director (Navy), Assistant Chief of Naval Staff (Support), Assistant Chief of the Naval Staff (Aviation & Carriers), and Ministry of Defence, Head Office Director of Strategic Projects to deliver a Command Plan that meets the Ministry of Defence Outputs.

The office holder is superintended by the Second Sea Lord and Deputy Chief of the Naval Staff.

[2] From April 2013 until November 2018 the post holder simultaneously held the title Chief of Staff Navy Command (HQ).