Nathan Francis Mossell (July 27, 1856 – October 27, 1946) was an American physician who was the first African-American graduate of the University of Pennsylvania School of Medicine in 1882.

He was active in the NAACP and also helped found the Frederick Douglass Memorial Hospital and Training School in West Philadelphia in 1895, which he led as chief-of-staff and medical director until he retired in 1933.

According to Mossell's autobiography, his mother's stories of the discrimination and hardship their families faced strengthened her own children's determination to succeed.

He married and settled in Baltimore, but the entire family, including Mossell's mother, who was a child at the time, were deported to Trinidad.

He eventually joined his elder brother Charles at Lincoln University, a historically black college in Pennsylvania, where he studied Natural Science, receiving his Bachelor of Arts degree in 1879.

In 1895, he helped found the Frederick Douglass Memorial Hospital and Training School in West Philadelphia, serving as its chief-of-staff and medical director until his retirement in 1933.

Gertrude was the mixed-race daughter of Charles Hicks Bustill (1816–1890), who was of African, European and Lenape ancestry, and Emily Robinson.