Oestridae (commonly called bot flies or botflies) is a family of Oestroidea. It is one of several families of hairy flies whose larvae live as parasites within the bodies of mammals. There are approximately 150 known species worldwide.

Only one bot fly species attacks humans, Dermatobia hominis. For many years the deer botfly was cited as the fastest flying insect in the Guinness Book of World Records, but the claim has been refuted and is no longer considered probable.