The present study aimed to investigate the valorization of Refused Derived Fuel (RDF) produced from solid waste management units for energetic uses, through its co-gasification with agricultural or forest wastes and carbon dioxide agents. Experiments were conducted using a fixed bed reactor and a thermal analysis system. The thermal behavior, the reactivity, the conversion, and the cold gas efficiency up to 950°C were evaluated based on the structural characteristics and inherent minerals of the materials, as well as on the basis of alkali catalysts and bio-oils admixed. Kinetic analysis of the co-gasification process was performed by developing an independent parallel reactions model. Blending RDF with the woody wastes at mass ratios 30:70 increased the conversion from 55% up to 86.4%. Gasification reactivity followed the order cotton stems>sunflower>pine cones>RDF. The addition of alkali compounds at low loadings as external catalysts enhanced conversion up to 100% and the process, in general, took place at much lower temperatures. The catalytic activity followed the order: CaO> Li2CO3>K2CO3. The addition of bio-oil at ratios 1:1 increased the conversion up to values 85-92%. The kinetic model applied was proven very successful, with deviation values below 5%. In presence of 10% wt, CaO the activation energy values of biochars were lowered from 148-252 kJ/mol to 138-201 kJ/mol, implying a better performance.