Defects and process irregularities influence the bonding strength and thus the stability and lifetime of welded glass components. The present paper proposes to monitor the laser-based glass welding process by means of a single photodetector that records the radiation emitted from the laser-induced plasma. It is shown that the plasma emission provides information about irregularities of the welded seam height, gap bridging, process interruptions, and the position of the seam. The method is suitable for different welded glass types.