This paper reported an approach to improve the interaction between glass fiber (GF) and polypropylene (PP) through interfacial crystallization. The experimental results showed that polar nucleating agents had strong interaction with GF and tended to deposit on the surface of GF through the dip‐coating method. Since the nucleating agents had good lattice matching with PP, the modified GF could promote the interfacial crystallization of PP to increase the interfacial interaction between GF and PP and improve the performance of PP/GF composites. However, at high processing temperature, the nucleating agents dissolved into the polymer melts, and the nucleation on the GF surface for PP crystallization decreased, impairing the interface compatibility and the final performance of the PP/GF composites. J. VINYL ADDIT. TECHNOL., 23:284–289, 2017. © 2015 Society of Plastics Engineers