This paper evaluates an effective interfacial agent, poly(propylene-co-1-hexen-6-ol) (hydroxylated polypropylene, PP-OH), that improves the adhesion between polypropylene (PP) and glass. Owing to the unique brush-like microstructure of PP-OH, with flexible primary hydroxy groups and long sequences of propylene units. the hydroxy groups effectively form chemical bonds with the free silanol groups on the glass surface, and the PP segments cocrystallize with isotactic PP. The strong interfacial interactions are shown in 90-degrees peel tests of PP/glass laminates. Both scanning electron microscopy and contact-angle studies on the fracture surfaces indicate no adhesive failure during peeling. In addition, differential scanning calorimetry studies demonstrate the cocrystallization between PP and PP-OH, and reflection infra-red results provide direct evidence of chemical bonding between PP-OH and glass surfaces.