An optoelectronic sensor (10), in particular a laser scanner, is provided which comprises a light transmitter (12) for transmitting a light beam (16) having a beam profile (28) elongated in a line direction into a monitored plane (26), a light receiver (34) for generating a received signal from the light bream (30) remitted by objects in the monitored plane (26), a movable deflection unit (24) for the periodic deflection of the light beam (16, 30) to scan the monitored plane (26) in the course of the movement and an evaluation unit (42) for detecting the objects with reference to the received signal. The laser scanner has an optical beam rotation element (20) which is disposed after the light transmitter (12) and which can tilt the line direction of a light beam (16) passing through.