The pie may get its name because the sweet molasses odor attracts flies that must be "shooed" away.
The shoofly pie's origins may come from the treacle tart with the primary difference being the use of molasses rather than golden syrup. A Montgomery pie is similar to a shoofly pie, except lemon juice is usually added to the bottom layer and buttermilk to the topping. A chess pie is also similar, but it is unlayered.
Shoofly pie also comes in two different versions – wet bottom and dry bottom. The dry bottom version is baked until fully set and results in a more cake-like consistency throughout. The wet bottom version is set like cake at the top where it has mixed in with the crumbs, but the very bottom is a stickier, gooier custard-like consistency.