A hybrid drive unit includes an internal combustion engine, electric machine, and transmission having an input shaft and first and second countershafts. The internal combustion engine is directly couplable via a clutch to the input shaft. There are six shiftable gear pairings, each with a gearwheel arranged coaxially to the input shaft. The first gear pairing has a first gearwheel as an idler gear arranged coaxially to the input shaft and a second gearwheel as an idler gear arranged coaxially to the first countershaft. The electric machine is connected to the first gear pairing so that torques are directable into the transmission via the first gear pairing. When viewed in an axial direction, the first shiftable gear pairing, a first shifting element plane, the second shiftable gear pairing, the third shiftable gear pairing, the fourth shiftable gear pairing, a second shifting element plane, the fifth shiftable gear pairing, the sixth shiftable gear pairing, and an output gear plane are arranged one after the other in the specified sequence.