There are many heavy oil reservoirs around the world, representing about 70% of the total oil resources. Primary heavy oil recovery is low, so enhanced oil recovery (EOR) methods are needed. Reducing the oil viscosity is a main mechanism of the recovery process, so thermal EOR methods are used. Conventional and unconventional thermal EOR methods face many challenges in recovering heavy oil, some of which can be overcome by nanotechnology. In this study, nanoparticles were used to enhance the heavy oil recovery by the Microwave Assisted Gravity Drainage (MWAGD) Process. Two types of metal oxide nanoparticles were used: gamma alumina (γ-Al2O3) and titanium (IV) oxide (TiO2), at four different concentrations. Besides studying the effect of nanoparticles on the recovery, the effect of water saturation on the oil recovery and the influence of nanoparticles on the emulsion viscosity and the thermal conductivity of distilled water were also investigated. The tests were done by using a heavy oil sample of 19 API and glass beads as a porous medium with an average porosity of 22%. The results showed that, in general, as the water saturation increases, the oil recovery from the MWAGD process rises, with optimum recovery occurring at a water saturation of 30%. In addition, the tests showed that recovery using microwave heating is higher than that with conventional heating. Also, each type of nanoparticle (γ-Al2O3 and TiO2) has its own trend in affecting either the emulsion viscosity or the water thermal conductivity due to variations in the physical properties of each nanoparticle such as shape and size. Al2O3 and TiO2 nanoparticles have the greatest effect on the oil recovery at low concentrations of 0.1 and 0.05 wt.%, respectively, during the MWAGD process. The tests showed that nanotechnology can be used to improve the performance and to overcome challenges facing thermal EOR methods, especially the unconventional methods.