Abstract: With the improvement of high-rise buildings, as well as of large-span and large-scale engineering projects, moreandmore high-performance structural concrete is required in the construction industry to cope with complicate anddiverseengineering demands. A significant amount of recent research has focused on high strength, high-toughness, light-weight andeconomic friendly concrete materials. Among them, the Structural Light Weight Concrete (SLWC) uses high-strengthlightweightaggregate instead of natural stone; this change of raw material makes it different from ordinary concrete in many aspects:itsdensity is below two thousands kilograms per meter cube while that of Normal Concrete (NC) is twenty four hundredkilogramsper meter cube besides, compared to NC, its strength per weight ratio is higher. SLWC has numerous advantages over NCInthisresearch, the flexural behaviour of light weight aggregate concrete with inclusion of steel and glass fibers were investigated. Themethodology consisted of comparing the results of conventional concrete, plain Light Weight Concrete (LWC) and fiber reinforcedLWC. The fibers were added in the LWC to reduce the brittleness of the concrete in order to increase the energy absorption capacity and to control the faster rate of crack development. As a result of this study the performance of the lightweight reinforced concrete beam was increased with the inclusion of fibers. Keywords: High-rise buildings, fiber reinforced, lightweight reinforced concrete, glass fibers, compressive strength