Sir Alexander Abercromby of Birkenbog, 1st Baronet (c. 1603 – December 1684) was a Scottish politician. He was the oldest son of Alexander Abercromby of Birkenbog and his wife Elizabeth Bethune, daughter of David Bethune. On 20 February 1636, he was created a Baronet, of Birkenbog, in the County of Banff. Abercromby entered the Parliament of Scotland in 1640, sitting for Banffshire until the following year. He represented the constituency also in 1643 and after a break of three years, he was returned for it in 1646, a seat he held for the next two years. In 1661, he was again successful for Banffshire until 1663. Abercromby was a Covenanter and in 1645 took part at the Battle of Auldearn under command of John Hurry.