William Paine (June 5, 1750 – April 19, 1833) was a physician and political figure in New Brunswick.

He was born in Worcester, Massachusetts, the son of Timothy Paine and Sarah Chandler.

He was educated at Harvard College, then studied medicine with Doctor Edward Augustus Holyoke and set up practice in Worcester in 1771.

He was censured for his protest and, later that year, travelled to England to continue his medical studies.

He served on the city council in 1785 and was elected to the legislative assembly later that year.