A temperature measurement system for a light emitting diode assembly that includes an LED having two semiconductors (28, 30) joined together at an LED junction, said system comprising: a temperature sensor operatively connected to the LED assembly at a remote location that is remote from the LED junction, the temperature sensor being configured to measure a temperature of the LED assembly at the remote location; a reference temperature sensor for measuring a reference temperature, the reference temperature being the temperature of ambient air proximate the LED assembly, or the temperature of a component that is external to the LED assembly; and a temperature calculation module operatively connected to the temperature sensor for receiving the measured temperature at the remote location from the temperature sensor, and operatively connected to the reference temperature sensor for receiving the reference temperature, wherein the temperature calculation module is configured to determine a junction temperature (T j) at the LED junction by comparing the measured temperature at the remote location with the reference temperature, characterised in that the temperature calculation mo dule is configured to determine the junction temperature (T j) based on the measured temperature at the remote location by comparing a measured electrical resistance (R t) of the temperature sensor at the remote location and a measured electrical resistance (R i) of the reference temperature sensor using the equation: R t = R i (1 + α T T j); wherein: R t = a measured electrical resistance of the temperature sensor at the remote location; R i = a measured reference electrical resistance of the reference temperature sensor; α T = error; and T j = the junction temperature. a temperature sensor operatively connected to the LED assembly at a remote location that is remote from the LED junction, the temperature sensor being configured to measure a temperature of the LED assembly at the remote location; a reference temperature sensor for measuring a reference temperature, the reference temperature being the temperature of ambient air proximate the LED assembly, or the temperature of a component that is external to the LED assembly; and a temperature calculation module operatively connected to the temperature sensor for receiving the measured temperature at the remote location from the temperature sensor, and operatively connected to the reference temperature sensor for receiving the reference temperature, wherein the temperature calculation module is configured to determine a junction temperature (T j) at the LED junction by comparing the measured temperature at the remote location with the reference temperature, characterised in that the temperature calculation mo dule is configured to determine the junction temperature (T j) based on the measured temperature at the remote location by comparing a measured electrical resistance (R t) of the temperature sensor at the remote location and a measured electrical resistance (R i) of the reference temperature sensor using the equation: R t = R i (1 + α T T j); wherein: R t = a measured electrical resistance of the temperature sensor at the remote location; R i = a measured reference electrical resistance of the reference temperature sensor; α T = error; and T j = the junction temperature. R t = a measured electrical resistance of the temperature sensor at the remote location; R i = a measured reference electrical resistance of the reference temperature sensor; α T = error; and T j = the junction temperature.