A semiconductor laser diode is provided. In an embodiment the semiconductor laser diode includes a semiconductor layer sequence having semiconductor layers disposed vertically one above the other. An active layer includes an active region having a width of greater than or equal to 30 μm emitting laser radiation during operation via a radiation coupling-out surface. The radiation coupling-out surface is formed by a lateral surface of the semiconductor layer sequence and forms, with an opposite rear surface, a resonator having lateral gain-guiding in a longitudinal direction. The semiconductor layer sequence is heated in a thermal region of influence by reason of the operation. A metallization layer is in direct contact with a top side of the semiconductor layer sequence.