Lord William Gordon (1744–1823) was a Scottish nobleman.
He was the second son of Cosmo Gordon, 3rd Duke of Gordon (1720–1752) and his wife Lady Catherine Gordon (c. 1725 – 10 December 1779), daughter of William Gordon, 2nd Earl of Aberdeen. His elder brother was Alexander Gordon, 4th Duke of Gordon (1743–1827). His younger brother was the controversial Lord George Gordon, notorious for the anti-Catholic riots named after him. He also had a sister, Lady Susan Gordon.
In the mid-1760s, Lord William had an affair with a married woman, Lady Sarah Bunbury, who was in fact his first cousin, and had once been courted by King George III. In 1768, he fathered a child upon Lady Sarah, a daughter who was not immediately disclaimed by Sir Charles Bunbury, and received the name Louisa Bunbury. Nevertheless, Lady Sarah and Lord William eloped shortly afterwards, taking the infant with them. Lord William soon tired of his lover's incessant demands for attention, gifts and ceaseless entertainments and abandoned her. Her husband refused to take her back, and Lady Sarah returned to her brother's house with her child, while her husband, Sir Charles, moved Parliament for a divorce on grounds of adultery, citing her elopement, not the birth of Louisa. It was not until 1776 that the decree of divorce was issued.The affair with Lady Sarah ruined William's social reputation, and also his military and political career.
Several years after the Bunbury affair, Lord William married the Hon. Frances Ingram-Shepheard, daughter of Charles Ingram, 9th Viscount of Irvine. They had one daughter, Frances Gordon, who died unmarried. His wife died in 1841.
While married to the Hon. Frances, Lord William had another affair and fathered an illegitimate son, William Conway Gordon (1798–1882). He arranged for the boy to receive an education and settled a reasonable income upon him. William Conway Gordon served as ADC to General Sir Peregrine Maitland, a relative by marriage of Lord William, being a distant cousin of the Hon. Frances.