Jozef Stefaan "Jeff", Baron Schell (20 July 1935 – 17 April 2003) was a Belgian molecular biologist.

[1][2] Schell studied zoology and microbiology at the University of Ghent, Belgium.

Schell was a pioneer in genetics who focused on the interaction between plants and soil bacteria.

Along with his colleague, Marc Van Montagu, Jeff Schell discovered the gene transfer mechanism between Agrobacterium and plants, which resulted in the development of methods to alter Agrobacterium into an efficient delivery system for gene engineering in plants.

Besides being a prominent scientist, in 1982 he co-founded, with Marc Van Montagu, the successful biotech company Plant Genetic Systems Inc., now part of Bayer CropScience.