In this study, surface modification of a silane-crosslinked polyethylene (Si-XLPE) compound was carried out by gliding arc atmospheric plasma. Samples were exposed to the plasma for different durations and the plasma-induced alterations of the surfaces were comprehensively assessed. Surface chemistry was evaluated initially via Fourier transform infrared spectroscopy (ATR-FTIR) and energy-dispersive X-ray (EDX) analysis. Surface morphology was investigated by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). For calculating surface free energy (SFE), contact angle measurement (CAM) was performed. In order to have accurate details on the surface chemistry and morphology, X-ray photoelectron spectroscopy (XPS) and Grazing Incidence X-ray Diffraction (GIXRD) analysis were conducted, respectively. Results revealed that this modification method doubled the amount of atomic oxygen and nitrogen on the surface, indicating the formation of polar chemical components on the surface. Moreover, plasma could change the surface morphology considerably by selective etching and impacting on roughness. Furthermore, it was observed that the modification improved the surface crystallinity to some extent and also increased SFE drastically. Surface modification of Si-XLPE by gliding arc plasma has then proved to be an effective technique during which noticeable improvement in wettability has occurred.