A methacrylate based gel polymer electrolyte (GPE) was prepared and electrochemically investigated. The polymer was synthesized as a statistical co-polymer of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) and benzyl methacrylate (BnMA) by free radical polymerization. The ethylene glycol side chain of OEGMA should be able to interact with the liquid electrolyte, thus keeping it inside the GPE, whereas BnMA was used to enhance the mechanical stability of the GPE. Such a polymer was able to retain liquid electrolyte up to 400% of its own weight, while the mechanical stability of the GPE was still high enough to be used as separator in lithium-ion batteries. The GPE displayed a conductivity of 1.8 mS cm−1 at 25 °C and an electrochemical stability window comparable to that of a standard liquid electrolyte. When used in lithium-ion batteries, such a GPE allowed a performance comparable to that obtained using conventional liquid electrolytes. Therefore the reported electrolyte was identified as a promising candidate as electrolyte for lithium-ion batteries.