One of the most important steps during the production of adhesively bonded fiber metal laminates (FMLs) is adhesive bonding. In glass fiber reinforced polypropylene/aluminum laminates, it is very difficult to provide good bond strength. In order to solve this problem, applying various surface pre-treatments to the bonding surfaces prior to adhesively bonded is very important for good performance properties. In the present study, glass fiber reinforced polypropylene (GFPP) composite plates were manufactured from (±450) fabrics using hot press compression method. Tensile, Charpy impact and flexural tests were performed to investigate the mechanical properties of the composites. The produced GFPP plate and Al were used as the adherends and polyurethane-based film as adhesive in FMLs. While manufacturing FMLs, various surface modification techniques (silane and sandblasting pre-treatment) were applied to aluminum for good adhesion of GFPP and Al interface and their effect on the adhesive properties of GFPP/Al laminates were presented. The mechanical properties lap shear, and flexural strength and Mode-I fracture toughness of the adhesively bonded Al/GFPP laminates were investigated to evaluate the effects of surface treatments. Scanning electron microscope (SEM) was used to examine the fracture surfaces. Single lap shear test showed that the adhesion of the GFPP/Al was improved by treatments of aluminum surfaces with silane and sandblasting. According to Mode-I fracture toughness values, silane treated specimens gave the best results. Based on the flexural test results, no significant change was observed in the flexural strength values of treated specimens compared to non-treated specimens.