Sir William Nicholson (1872—1949) was a British painter, also known for his work as an illustrator and author of children's books.

William Nicholson (1753—May 21, 1815) was a renowned English chemist who was also a writer on natural philosophy and chemistry as well as a translator, journalist, publisher, scientist, and inventor.

William Carmichael Nicholson (circa 1790—25 July 1872) was an officer in the United States Navy during the War of 1812 and the Civil War.

William Nicholson (27 February 1816—10 March 1865) was an Australian colonial politician who became the third Premier of Victoria. He is remembered for having been called the "father of the ballot" due to his responsibility in introducing the secret ballot in Victoria.

William Nicholson (born January 12, 1948) is a BAFTA-, Oscar- and Tony-nominated British screenwriter, playwright, and novelist.