In today's construction industry, concrete is one of the most commonly used building materials. Fine aggregates, coarse aggregates, cement, and water are main ingredients that produce concrete. Concrete has a high compressive strength but a low tensile strength. It is brittle, and if subjected for tensile force to it, it will break. As concrete cracks, it loses the ability to support tensile loads. Fibers, which is good in tensile force resistance, are added to concrete to improve tensile and flexural strength. The purpose of this study is to assess the effect of glass fibers on the mechanical and fracture properties of concrete at elevated temperatures using experimental methods. In this research, beams, cubes and cylinder specimens were used to study the effect of glass fiber on concrete. Specimens were casted using three percentages of glass fiber which are 0%, 0.3% and 0.6% and were cured in 28 days. After curing, the samples are heated at three temperature rates that are 100 ºC, 200 ºC and 300ºC for one hour and two hours. The 3-point bending test was performed in a displacement control electro-hydraulic servo universal testing machine at a constant displacement rate of 0.1mm/s to determine the fracture energy of glass fiber concrete that is exposed to elevated temperature by using notched beam test specimens. This test is carried out in accordance with the RILEM TC 50-FMC Recommendation (Work of Fracture Method). The compressive strength test was carried out in accordance with EN 12390-3:2009, Testing hardened concrete part 3: Compressive strength of test specimens for determination of compressive strength of the material and the split tensile strength test was carried out in accordance with EN 12390-6:2009, Testing hardened concrete part 6: Tensile strength of test specimens for determination of tensile strength of the material. The result shows that temperature has an adverse effect on the fracture energy, compressive and tensile strength of plain and glass fiber concrete. The percentage decrease of fracture energy due to temperature rate in 0.3 % of glass fiber concrete is 12.63% and 38.19% for one hour and 17.25% and 31.38% for two hours, and for 0.6% of glass fiber concrete, the percentage reduction of fracture energy is 31.41 % and 48.02 % for one hour and 16.85% and 46.82% for two hours. The addition of glass fiber greatly improves the fracture energy of plain concrete when exposed to high temperatures and the addition of glass fiber to plain concrete makes it more ductile and increases the crack width