The aim of this study is to demonstrate whether Carpinus betulus L. (CB) powder can be used as an alternative filler/reinforcement material for polypropylene (PP). About 5, 10, 15, and 20 wt% CB loaded PP composites were prepared by a high-speed thermokinetic mixer. In this article, the effects of weight fraction of CB within PP on thermal, viscoelastic, chemical, mechanical, crystallographic, and morphological properties of PP composites were investigated by tensile and three-point bending test, dynamic mechanic analysis, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared analysis, and scanning electron microscopy. Melting temperature of the composites decreased with the increase of CB content. The crystallization temperature of PP increased with the addition of CB into PP. When 10 wt% CB filler was loaded into PP, the tensile of PP increased by about 29 wt%. The storage modulus of PP were remarkably enhanced with increasing CB weight fraction. About 5 wt% CB addition into PP increased the flexural strength of PP by about 32%.