Alexander Wentworth Macdonald, 2nd Baron Macdonald (9 December 1773 – 19 June 1824) was a Scottish peer and Member of Parliament. Macdonald was the eldest son of Alexander Macdonald, 1st Baron Macdonald of Skye, Scotland, and his wife Elizabeth Diana (née Bosville). He succeeded his father to the barony in 1795 but, as this was an Irish peerage, it did not entitle him to a seat in the British House of Lords. The following year he was instead elected to the House of Commons for Saltash, a seat he held until 1802.