An optical sheet includes a first wedge layer having a first refractive index and including a wedge-shaped prism pattern including an inclined surface having an inclination angle with respect to a plane defined by a first direction and a second direction perpendicular to the first direction and a vertical surface extending in a third direction perpendicular to the first direction and the second direction, a second wedge layer disposed on the first wedge layer and having a second refractive index greater than the first refractive index, and a light blocking pattern disposed between the first wedge layer and the second wedge layer and including a first surface that contacts with the vertical surface and a second surface inclined to have the inclination angle with respect to the plane while contacting with the inclined surface.