Arthur James Balfour, 1st Earl of Balfour, KG, OM, PC, FRS, FBA, DL 25 July 1848 – 19 March 1930), also known as Lord Balfour, was a British Conservative statesman who served as Prime Minister of the United Kingdom from 1902 to 1905.

As foreign secretary in the Lloyd George ministry, he issued the Balfour Declaration in 1917 on behalf of the cabinet.