Geosynthetics have been used as reinforcement and stabilization elements in the base and subbase layers of flexible pavements, as well as reinforcement inclusion in the asphalt concrete wearing surface, particularly mitigating asphalt reflective cracks and rutting. Recently, the use of geogrids as reinforcement elements has expanded into Portland cement concrete (PCC) pavements, as an alternative to steel reinforcements. Although not yet so explored in the literature, the use of geogrids in PCC gives a new employment area for the Geosynthetics. This research presents an experimental investigation on the flexural behavior of geogrid-reinforced concrete beams under four-point bending test. Three different types of geogrids (aperture size and shape, physical and mechanical properties, and material composition) were used. The PCC mix was prepared using Type I Portland cement with flexural strength of 4.8 MPa and a compressive strength of 35 MPa. Nine concrete slab specimens (500 × 150 × 150 mm) were tested under monotonic load. Results confirmed that the flexural performance and cracking resistance of the concrete slab specimens reinforced with geogrids can be improved, as evidenced by load-deflection response, load capacity and failure mode.