Polymer-based materials are mainly intended for structural applications in industries. Due to their competitive properties, they are used as a replacement for wood and other conventional materials. During their manufacture, fibres are reinforced into the polymer resin in different shapes as required. Among several available reinforcements, glass fibre in many researches showed the best in mechanical characters, ability to get reinforced in the matrix and handling ability. In contrast, bio-reinforcements from various natural sources are also used as an alternative and they provide an equal performance like the man-made reinforcements. When both the artificial fibre and natural fibre are used in a composite material, the composite attains the iconic characters of each reinforcement; thus, the material as a whole shows excellent characteristics. This chapter provides a clear picture on characterization of composites with glass reinforcement in sandwich form, and also shows various trends like the elevation or decline in their strengths, their possible reasons and the potential ways for elevating the characters of the composite.