Admiral Frederick Augustus Maxse (13 April 1833 – 25 June 1900) was a British Royal Navy officer and radical liberal campaigner. The younger son of James Maxse who won the very first King's Cup in 1827.
Maxse was born in London, the son of James Maxse and Lady Caroline FitzHardinge, daughter of Frederick Augustus, 5th Earl of Berkeley. His elder brother was Sir Henry Berkeley Fitzhardinge Maxse.
Maxse was naval aide-de-camp to Lord Raglan after the Battle of the Alma on 20 September 1854 in the Crimean War. He was an atheist and vegetarian.
Maxse retired from the Royal Navy in 1867, but failed in his attempts to get elected to Parliament in 1868 and 1874. Maxse was active in various causes including the Charity Organisation Society, John Stuart Mill's Land Tenure Reform Association, the National Education League and the Eastern Question Association, founded to campaign against the atrocities of the Ottoman Empire during the Bulgarian April Uprising of 1876. He also founded the Electoral Reform Association which campaigned for the equalisation of parliamentary constituencies.
He died in London