A light emitting diode (LED) lamp tube includes a tubular enclosure extending along an axial direction and having an inner peripheral surface. A lamp device is disposed in the enclosure, and includes a circuit board, and a plurality of LEDs electrically connected to the circuit board. Two connectors are disposed respectively at two ends of the enclosure and are electrically connected to the circuit board. The connectors are adapted to be electrically connected to a power source. An optical film unit is disposed on the inner peripheral surface of the enclosure. The optical film unit has a film body and a plurality of protrusions arranged along the axial direction and protruding from the film body toward the inner peripheral surface of the enclosure.