Disclosed are a field effect transistor and a method of manufacturing the same. The field effect transistor includes a source electrode on a substrate, a drain electrode separated from the source electrode, and channels connected between the source electrode and the drain electrode, gate insulating layers, and a gate electrode. The channels may have a hollow closed cross-sectional structure when viewed in a first cross-section formed by a plane across the source electrode and the drain electrode in a direction perpendicular to the substrate. The gate insulating layers may be in the channels. The gate electrode may be insulated from the source electrode and the drain electrode by the gate insulating layers.