An optoelectronic sensor for detecting objects in a monitored zone in accordance with the triangulation principle, said optoelectronic sensor comprising a transmission arrangement for transmitting transmission light signals into the monitored zone along a transmission light path, wherein the transmission arrangement comprises at least one light source and a transmission optics which is configured to focus the transmission light signals generated by the at least one light source into a transmission light spot, and a reception arrangement - which comprises a reception optics which is configured to focus reception light signals, which are generated by an object present in the monitored zone by a remission of incident transmission light signals, into a reception light spot, and - a spatially resolving light receiver which is configured to detect the reception light spot, wherein the point of incidence of the reception light spot on the light receiver with respect to a triangulation direction depends on the distance of the object from the optoelectronic sensor, wherein the light receiver faces the monitored zone and the at least one light source is arranged facing away from the monitored zone, and wherein the transmission arrangement comprises at least one deflection element which is configured to deflect the transmission light signals, which are initially transmitted in a direction facing away from the monitored zone by the at least one light source, in the direction of the monitored zone, wherein the at least one light source and the light receiver are arranged on a common carrier board of a planar design, characterized in that the carrier board has a first side facing the monitored zone and forming a front side of the carrier board and a second side facing away from the monitored zone and forming a rear side of the carrier board, with the light receiver being arranged at the first side and the at least one light source being arranged at the second side. said optoelectronic sensor comprising a transmission arrangement for transmitting transmission light signals into the monitored zone along a transmission light path, wherein the transmission arrangement comprises at least one light source and a transmission optics which is configured to focus the transmission light signals generated by the at least one light source into a transmission light spot, and a reception arrangement - which comprises a reception optics which is configured to focus reception light signals, which are generated by an object present in the monitored zone by a remission of incident transmission light signals, into a reception light spot, and - a spatially resolving light receiver which is configured to detect the reception light spot, wherein the point of incidence of the reception light spot on the light receiver with respect to a triangulation direction depends on the distance of the object from the optoelectronic sensor, wherein the light receiver faces the monitored zone and the at least one light source is arranged facing away from the monitored zone, and wherein the transmission arrangement comprises at least one deflection element which is configured to deflect the transmission light signals, which are initially transmitted in a direction facing away from the monitored zone by the at least one light source, in the direction of the monitored zone, - which comprises a reception optics which is configured to focus reception light signals, which are generated by an object present in the monitored zone by a remission of incident transmission light signals, into a reception light spot, and - a spatially resolving light receiver which is configured to detect the reception light spot, wherein the point of incidence of the reception light spot on the light receiver with respect to a triangulation direction depends on the distance of the object from the optoelectronic sensor, wherein the light receiver faces the monitored zone and the at least one light source is arranged facing away from the monitored zone, and wherein the transmission arrangement comprises at least one deflection element which is configured to deflect the transmission light signals, which are initially transmitted in a direction facing away from the monitored zone by the at least one light source, in the direction of the monitored zone, wherein the at least one light source and the light receiver are arranged on a common carrier board of a planar design, characterized in that the carrier board has a first side facing the monitored zone and forming a front side of the carrier board and a second side facing away from the monitored zone and forming a rear side of the carrier board, with the light receiver being arranged at the first side and the at least one light source being arranged at the second side.