This experimental work presents results on the effect of different concrete types on the flexural behavior and deflection of beams reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. Four different types of concretes namely; ordinary Portland concrete (OPCC), fiber reinforced concrete (FRC), geopolymer concrete (GPC), and fiber reinforced geopolymer concrete (FRGC) were used. A total of eight beams were subjected to four-point static bending tests. The parameters studied were load capacities, deflection, and strain development in concrete and rebars, while cracking patterns and failure modes were also observed. All tested beams exhibit comparable flexural and deflection characteristics. The results indicate that GPC and FRGC beams were more effective for a GFRP reinforced system than ordinary concrete. The ACI 440-R1-06 equations gave conservative estimates for both the flexural capacity and the deflection of the members and therefore may be used irrespective of the concrete type.