The Second Sea Lord is one of the senior admirals of the Royal Navy. The Second Sea Lord was formerly the second most senior naval member of the Board of Admiralty, but is now considered to be junior to both the First Sea Lord and the Commander-in-Chief Fleet.

The Second Sea Lord is the senior officer responsible for personnel in the Royal Navy and is currently also Commander-in-Chief Naval Home Command, and is known by the abbreviations 2SL/CNH. This latter role officially gives him a flagship, HMS Victory at Portsmouth, England, although in practice it is a museum ship in dry dock.

The current Second Sea Lord is Vice-Admiral Sir James Burnell-Nugent (appointed 2003).