An optoelectronic sensor for detecting objects in a three-dimensional monitored zone which has a plurality of scanning zones, said optoelectronic sensor comprising a light transmission unit for transmitting a transmission light beam into the monitored zone; a spatially resolving light reception unit having corresponding reception optics and a plurality of reception zones for generating reception signals from a transmission light beam remitted or reflected in the monitored zone, wherein a respective scanning zone is associated with each reception zone such that only a transmission light beam remitted or reflected within the associated scanning zone is received by the associated reception zone; a scanning apparatus which has a base which rotates about an axis of rotation and at which the light transmission unit and the light reception unit are jointly held such that the scanning apparatus is configured for a periodic change of the propagation direction of the transmission light beam and for a change of the detection direction of the light reception unit that is synchronous with said periodic change; and an evaluation unit which is configured to detect the objects on the basis of the reception signals, characterized in that the light transmission unit comprises a light transmitter for generating the transmission light beam and a beam splitting device for splitting the transmission light beam into a plurality of part transmission light beams spatially separated from one another, and in that the sensor further comprises a trapezoidal carrier which is held at the base and which carries an assembly of the reception optics and the beam splitting device spaced apart from the base. a light transmission unit for transmitting a transmission light beam into the monitored zone; a spatially resolving light reception unit having corresponding reception optics and a plurality of reception zones for generating reception signals from a transmission light beam remitted or reflected in the monitored zone, wherein a respective scanning zone is associated with each reception zone such that only a transmission light beam remitted or reflected within the associated scanning zone is received by the associated reception zone; a scanning apparatus which has a base which rotates about an axis of rotation and at which the light transmission unit and the light reception unit are jointly held such that the scanning apparatus is configured for a periodic change of the propagation direction of the transmission light beam and for a change of the detection direction of the light reception unit that is synchronous with said periodic change; and an evaluation unit which is configured to detect the objects on the basis of the reception signals, characterized in that the light transmission unit comprises a light transmitter for generating the transmission light beam and a beam splitting device for splitting the transmission light beam into a plurality of part transmission light beams spatially separated from one another, and in that the sensor further comprises a trapezoidal carrier which is held at the base and which carries an assembly of the reception optics and the beam splitting device spaced apart from the base.