A turbine blade having cooling holes formed therein and a turbine including the same are provided. The turbine blade includes an airfoil having a leading edge and a trailing edge formed thereon and a cooling passage defined for flow of a cooling fluid therethrough, and a cooling hole configured to communicate between the cooling passage and outside in the airfoil and having an inlet and an outlet, wherein the cooling hole includes an expanded portion and a grooved portion formed in the outlet, the grooved portion being recessed from the expanded portion toward the trailing edge.