UHMWPE filaments have a low surface free energy and therefore often require a modification of their surface properties before any use. Atmospheric pressure plasmas treatment is a convenient and environmentally friendly way to obtain these modifications by introducing new chemical groups at the surface without affecting the bulk properties. This paper studies the influence of nano-SiO2 sol-gel coating pretreatment on atmospheric pressure plasma jet (APPJ) treatment of ultrahigh molecular weight polyethylene (UHMWPE) fibers when a mixture of 100% helium and 1% oxygen used as the treatment gas. The surface properties of the plasma-treated UHMWPE filaments are characterized using contact angle measurements and ATR-FTIR spectroscopy. The UHMWPE filaments show a remarkable increase in surface free energy after plasma treatment. ATR-FTIR spectroscopy of the plasma-treated UHMWPE filaments reveals that plasma treatment introduces oxygen-containing functionalities on the UHMWPE filaments surface leading to the increased surface free energy.