A track lighting system comprising: an elongated power track extending in a longitudinal direction and being connectable to a power supply, and a light emitting diode module, wherein the power track and the LED module are configured to be connected to one another, and wherein the power track is configured to provide electric output and to form a base for mounting the LED module to a surface, wherein the LED module comprises an elongated optical component extending in the longitudinal direction and an LED component with at least one integrated LED light source configured to, in operation, emit light, wherein the optical component is arranged to at least partly enclose the power track when the power track and the LED module are mechanically and electrically connected, wherein the optical component comprises a light in-coupling section facing the LED light source in the LED component when the power track and the LED module are mechanically and electrically connected, said light in-coupling section being configured to couple light emitted by the LED light source into the optical component, and wherein the optical component comprises a light out-coupling section configured to couple light out of the optical component and is arranged to direct the emission of light in directions away from the power track, when the power track and LED module are connected, and wherein the optical component is a light guide made of a transparent or translucent material and comprises light out-coupling elements configured to facilitate light out-coupling, wherein at least part of in-coupled light is light guided through the light guide via total internal reflection from the light in-coupling section to the light out-coupling section. an elongated power track extending in a longitudinal direction and being connectable to a power supply, and a light emitting diode module, wherein the power track and the LED module are configured to be connected to one another, and wherein the power track is configured to provide electric output and to form a base for mounting the LED module to a surface, wherein the LED module comprises an elongated optical component extending in the longitudinal direction and an LED component with at least one integrated LED light source configured to, in operation, emit light, wherein the optical component is arranged to at least partly enclose the power track when the power track and the LED module are mechanically and electrically connected, wherein the optical component comprises a light in-coupling section facing the LED light source in the LED component when the power track and the LED module are mechanically and electrically connected, said light in-coupling section being configured to couple light emitted by the LED light source into the optical component, and wherein the optical component comprises a light out-coupling section configured to couple light out of the optical component and is arranged to direct the emission of light in directions away from the power track, when the power track and LED module are connected, and wherein the optical component is a light guide made of a transparent or translucent material and comprises light out-coupling elements configured to facilitate light out-coupling, wherein at least part of in-coupled light is light guided through the light guide via total internal reflection from the light in-coupling section to the light out-coupling section.