Gert Cornelius Nel (6 April 1885 – 16 February 1950) was a South African botanist.
The genus Nelia, a flowering plant of the family Aizoaceae, is named in his honor.
Nel emphasized African plant species in his studies, especially in the families Amaryllidaceae and Hypoxidaceae.
He provided numerous first descriptions of species of the genera Forbesia, Ianthe, Hypoxis, and Rhodohypoxis.
In 1921, Nel became a professor of botany at the University of Stellenbosch, a position he would hold until his death.