Alternative of using organic and biomass residues as additives or reinforcements in the production of composite materials has attracted great attention since the 2000s. However, when lignocellulosic biomass is used as natural fiber in composite production, it may have some disadvantages such as low interfacial bonding with the matrix phase. The most common methods used to strengthen the bonding between the matrix phase and the additive material is to use maleic anhydride (MA) as a compatibilizer and some chemicals such as dicumyl peroxide (DCP) as reaction initiators to increase the compatibilizing effect of MA. Therefore, in this study, olive pomace oil maleate (OPOMA) was prepared to be used in the production of polylactic acid (PLA) composites. Olive pomace obtained with ionic liquid pretreatment (OP-IL) in the previous studies of the authors and OPOMA were used in composite production with a biodegradable polymer of PLA. The composite was obtained by mixing 95PLA+5OP-IL by weight in twin-screw extruder at 190 ºC for 10 minutes. Under the same conditions, the effect of OPOMA was evaluated by adding 0.5%, 1% and 2% ratio to PLA + OP-IL. In FTIR spectrum of OPOMA, a new symmetrical and asymmetric C=O bands were formed differently from olive oil. While the tensile strength of the PLA+OP mixture was approximately 10 MPa; the tensile strength value of PLA+OP-IL and PLA+OP-IL+OPOMA was around 60 MPa. The elasticity modulus showed less change compared to other mechanical properties. To conclude, it can be emphasized that oil maleates of lignocellulosic biomasses can be promising compati-bilizer for biodegradable composite matrices.