The objective of the reported study was to investigate and evaluate the behaviour of one-way concrete slabs reinforced with glass-fibre-reinforced polymer (GFRP) rebars under distributed and line loads. A fibre-reinforced polymer (FRP) composite made with resin-impregnated continuous fibres is considered a promising alternative to traditional steel reinforcement. The experimental programme used eight GFRP concrete slabs to study the type of rebar (steel and GFRP), strength of concrete (25 and 45 MPa), reinforcement ratio and type of loading (distributed and line) loads. The results from a series of tests showed that strains of GFRP rebars are generally larger than those of steel rebars, increasing the ratios of the GFRP rebars led to an increase in ultimate flexural strength and increasing the concrete strength of the slabs led to an increase in slab rigidity, which improves flexural capacity. Furthermore, it was found that failure of slabs reinforced with GFRP rebars occurred by crushing and end slip of GFRP rebars must be prevented by using additional bars beyond the supports.