This study aims at the modification of the surface properties of twill-5 polyethylene terephthalate (PET) fabric, in particular to improve its hydrophilicity. It compares the hydrophilic potential and efficacy of two vinyl monomers radically grafted onto the fabric by photoinduced processes. Poly(ethylene glycol) diacrylate (PEGDA) and [2-(methacryloyloxy)-ethyl]-trimethylammonium chloride (METAC) affected the wettability of the fabric towards water, significantly reducing the water contact angle (WCA). As a consequence, the treated fabrics showed a good improvement of dynamic moisture management. Adopting specific conditions (e.g., type of monomer and grafting monomer concentration), the grafted PET fabrics remained hydrophilic after washing, laudering, dry cleaning, and rubbing tests; thus, the surface treatment modification resulted to be durable overall.