In cementitious composites, an application of various fibers can contribute to endow a controlled crack propagation, moderated brittle failure, superior tensile strength and higher energy absorption capacity. Fiber-matrix bonding properties play a key role in fiber strengthening efficiency and the final mechanical performances of the reinforced matrices. This is true specifically for high-performance polyethylene (PE) fibers which yield very high tensile strength and modulus of elasticity, but do not interact properly with cementitious matrix due to their inert hydrophobic surface lacking functional groups. In the presented work, PE fibers are functionalized by using fast tannic acid modification technique to enhance the bonding properties between a cementitious matrix and the fibers. Environmental scanning electron microscopy (ESEM) confirmed the presence of polymer coating layers on the fiber surfaces. Micromechanical tests indicated that the modified fibers considerably improved the maximum fiber pullout force, interfacial shear strength and pullout work in comparison with the reference fibers. This enhancement in bonding properties could be traced back to the created functional layer on the PE surface triggering a better interaction with cement hydrates as well as a rougher surface enhancing fiber-matrix mechanical interlocking at interfaces. Overall, the introduced approach can be applied for different fibers to promote their bonding behavior with cementitious matrices resulting in an enhanced fiber reinforcing effect in composites.