This is a list of people who have served as Lord-Lieutenant of Northumberland.
Since 1802, all Lords Lieutenant have also been Custos Rotulorum of Northumberland.
Deputy Lieutenants traditionally supported the Lord-Lieutenant.
There could be many deputy lieutenants at any time, depending on the population of the county.
Their appointment did not terminate with the changing of the Lord-Lieutenant, but they often retired at age 75.