The contact angle (CA) of lignocellulosic powder allows predicting important properties of a filled polymer composite material such as its wettability, adhesion, adsorption, etc. The contact angle and the surface free energy can be measured by the Washburn method, which is used to determine the capillary constant calculated from the penetration rate of a liquid into the compacted lignocellulosic powder, and by the Wilhelmy method based on measuring interface surface tension of the filled polymer composites. The aim of the work was to evaluate the wettability of the initial and the modified wood microparticles as well as the composite samples consisting of recycled polypropylene and the lignocellulosic microparticles, using contact angle, water sorption and Zeta potential (ζ) measurements. The contact angle was determined with a tensiometer Kruss 100M. The capillary constant (K) for each lignocellulosic powder was determined in n-heptane. The surface free energy was calculated using the approach suggested by Owens-Wendt-Kaeble. The Zeta potential of the microparticles was measured with a dynamic light scattering device Zetasizer Nano SZ. For the modification, at first, the hardwood lignocelluloses were treated with low temperature acid hydrolysis under mild conditions [1]. Then, the fractionated hydrolysed microparticles were modified to introduce the new functional groups at their surface. It was found that the hydrolysis and the modification of the lignocellulosic particles differently effect on their water wettability. While the hydrolysis of the lignocelluloses led to the increase in the negative Z potential values of the particles and the decrease in their contact angles, the modification essentially decreased the negative charge of the lignocellulosic microparticles and remarkably enhanced their contact angles in water.