István Apáthy, also known as Stephan Apáthy (1863–1922), was a Hungarianzoologist and histologist, known for his work in medical science and microscope technique. He particularly studied neurofibrils, and was known for improving microscopic techniques for dealing with tissue samples. Apáthy was a professor at the Franz Joseph University. He also theorized on the "social and political aspects" of eugenics.