Alexander Williams Biddle (April 29, 1819 – May 2, 1899) was an American businessman from Pennsylvania.

[3] In 1848, he joined his father's company, Thomas Biddle & Co., where he worked until the beginning of the Civil War.

On September 1, 1862, he joined the 121st Pennsylvania Volunteer Infantry and served under his cousin, Chapman Biddle.

His name is inscribed on the 121st Pennsylvania's monument along South Reynolds Avenue in the Gettysburg National Military Park.

After the war, he retired from Thomas Biddle & Company, and in 1874, he was named a director of the Pennsylvania Railroad.