Multibeam antennas have emerged as a promising concept for applications where selective beam coverage is required. Multibeam radiation can be achieved leveraging the concept of metasurfaces, enabling the radiated wavefronts to be tailored in an all-electronic manner, making reconfigurable multibeam operation possible without the need for bulky feeding structures or complex phase shifting circuits. Here we demonstrate a simple, planar, printed-circuit-board-based parallel-plate waveguide (PPW) holographic metasurface antenna capable of producing dual-polarized multibeam radiation patterns. The metasurface is synthesized using an array of subwavelength slot-shaped unit cells (or irises) coupling to a guided-mode reference wave launched into the PPW using a single coaxial feed. As a design example, we demonstrate numerically and experimentally a metasurface antenna creating polarization-dependent multibeam radiation patterns with three main lobes in azimuth and elevation planes.