Although glass fibre-reinforced polymer (GFRP) is increasingly being used as a substitute for steel reinforcements, there is a lack of studies on the fatigue performance of GFRP bars in reinforced concrete structures. This study examines the fatigue life of ribbed GFRP bars in concrete beams. The experimental program is set to test a concrete beam reinforced with GFRP under fatigue loading. The maximum fatigue tension stresses applied on the GFRP bars are designed to be 30% of the ultimate tensile strength (UTS). The paper also presents a testing methodology employing a displacement-controlled system for fatigue testing. This protocol specifically solves many problems related to force-controlled fatigue testing. This research indicates that ribbed GFRP bars can endure two million cycles of fatigue loading without failure, where the GFRP bars were under 30% of the UTS, with a stress ratio of 40%. The fatigue life achieved surpasses the results reported in previous studies, highlighting the influence of stress ratio and bar surface profile on fatigue performance.