A hybrid powertrain for a vehicle includes a first input shaft connected to an engine, a second input shaft connected to the engine and coaxially mounted with the first input shaft, a motor input shaft coaxially mounted with the first input shaft and connected to a motor, first and second output shafts mounted in parallel to the first input shaft and the second input shaft, first and second drive gears connected to the motor input shaft, a first driven gear engaged with the first drive gear, a second driven gear engaged with the second drive gear, a complex synchronizer to couple and separate the first input shaft and the motor input shaft and to couple and separate the first drive gear and the motor input shaft, a third clutch to couple and separate the second drive gear and the motor input shaft, and a plurality of external gear pairs configured to respectively define different gear ratios.