Catharine Weed Barnes (January 10, 1851 – July 31, 1913)
 was an early American photographer who later lived in England. She was a strong supporter of women photographers.
Catharine Weed Barnes was born in Albany, New York, the oldest child of well-to-do parents William Barnes and Emily P. (Weed) Barnes (daughter of the politician Thurlow Weed). She attended Vassar College but her time was cut short by familial obligations. In 1872, she went to Russia with her father, who was a delegate to an international congress.