An embodiment of the inventive concept provides a thin film transistor and a manufacturing method of the same. The manufacturing method includes forming a data electrode on one side of a substrate, forming a spacer layer on a portion of the data electrode and the other side of the substrate, forming a drain electrode on a top surface of the spacer layer, forming an active layer on a sidewall of the spacer layer, the drain electrode, and the data electrode, forming a gate insulation film that covers the active layer on the sidewall of the spacer layer, and forming a doped layer on the gate insulation film and the active layer outside the gate insulation film to form impurity regions at both sides, respectively, of the active layer.