In this study, jute fabrics/modified epoxy composites were fabricated by means of hand lay-up process. In order to enhance adhesion between the alkalized jute fabric and epoxy, modification processes was carried out by applying an oligomeric siloxane at different concentrations into epoxy matrix. The influence of resin modification processes on mechanical properties was examined. Tensile and flexural properties and interlaminar shear strength (ILSS) of the composites were measured. It was shown that the ILSS values are increased from 14.18 MPa for alkalized jute fabric/epoxy composite to 22.82 MPa for alkalized jute fabric/3% (w/w) oligomeric siloxane modified epoxy composite. The improved adhesion between the fiber and the matrix may be a result of modification of epoxy matrix with an oligomeric siloxane. This conclusion was confirmed by the morphology observations investigated by scanning electron microscopy. Besides, the modification of epoxy with 3% (w/w) oligomeric siloxane resulted in 30.4% increase in the tensile strength of alkalized jute fabric/epoxy composite. From results of the flexural modulus, application of oligomeric siloxane into epoxy matrix leads to much stiffer jute fiber-epoxy composite.