Lajos Méhelÿ (August 24, 1862 – February 4, 1953) was a Hungarian zoologist, herpetologist, professor, and prolific author.
He is one of the greatest, but also one of the most controversial, personalities in the history of Hungarian zoology because of his Social Darwinist and racialist publications.
He had been a member of the Hungarian Academy of Sciences but renounced his membership.
Besides his zoological work he increasingly dedicated his life to the Hungarian racial theory and Turanism.
As a result, he was imprisoned after the Second World War and spent his punishment as a war criminal against the people until his death in old age.