Sir Alexander Bannerman, 9th Baronet (6 April 1823 – 21 April 1877) was a Scottish diplomat.
Alexander was born on 6 April 1823. He was the eldest son of Sir Charles Bannerman, 8th Baronet (1782–1851), and Anne Bannerman, who were first cousins.
The Bannerman baronetcy was created in the Baronetage of Nova Scotia in 1682 by King Charles II on account of the 1st Baronet's "constant loyalty during the rebellion, and of the heavy calamities he had suffered on that account." His aunt, Maria Bannerman, was married to William Keith-Falconer, 6th Earl of Kintore, and were the parents of his cousin, Anthony Keith-Falconer, 7th Earl of Kintore. His uncle, Dr. James Bannerman, was a physician and professor like his paternal grandfather, Sir Alexander Bannerman, 6th Baronet. His maternal grandfather, Charles Bannerman, was the younger brother of his paternal grandfather, the 6th Baronet.
He was educated at Trinity College, Cambridge. He was attached to the British Legation at Florence between 1844 and 1847. Upon the death of his father on 18 June 1851, he succeeded as the 9th Baronet Bannerman of Elsick. He bought back part of the Elsick estate that had been sold by the 4th Baronet, who was forced to sell the estate for a nominal price on account of his father's and his alleged participation in the Jacobite rising of 1745.
He held the office of Vice-Lord Lieutenant of Aberdeenshire.