In the past two decades, a large number of research programmes focussed on short-term flexural behaviour of fibre reinforced polymer (FRP) reinforced concrete members has been carried out. However, the number of studies on the long-term behaviour is still scarce. In this research work, the long-term behaviour of FRP reinforced concrete beams has been investigated both analytically and experimentally to further extend the knowledge in this particular research domain. In this respect, a new methodology to predict long-term deflections due to creep and shrinkage is presented. Being simple and straightforward, the proposed methodology accounts for main mechanical properties of materials, variations in environmental conditions or other parameters that can affect creep and shrinkage of concrete. In addition, an experimental campaign GFRP reinforced concrete beams subject to long-term loading has been performed. The experimental long-term results are reported and discussed. Furthermore they are compared to predictions using the most representative procedures, as well as the proposed methodology presented in this work.