Most of the burners used in domestic gas stoves have a simple geometry and they are usually very similar in design. As a results newer and different burner styles are rarely seen even in newer stoves. Therefore, in the present study the effects of burner geometry on the thermal efficiency of gas stoves are investigated. Although there have been numerous experimental studies to determine the thermal efficiency of existing burners and the effects of different parameters to improve their thermal efficiency have been studied, there is still room to develop and study the performance of newer and different gas burner designs using computational techniques. In the present thesis, first, two of the most common burner designs have been experimentally studied according to the VITA standard and their thermal efficiencies are measured. Then these burners are numerically modelled and their steady state performances are simulated. It is then shown that both experimental and numerical results are in a good agreement. After setting up our computational model, the performance of some 7 new burner designs for domestic stoves are numerically modelled and studied. These burner designs have been categorized in three groups, 1-simple burners, 2-burners with inclined surfaces and 3-special design burners. In the first group commonly used burners exist with a difference in the shape of their gas outlet holes. The second group includes burners which have burner holes on two outer and inner inclined surfaces. The third group includes some newer and different burner designs. After numerically simulating the performance of these burners, contours of temperature and flow velocity are plotted and their thermal efficiencies are determined. Results show that using rectangular burner holes and inclined inner and outer surfaces on a burner would improve the burner thermal efficiency. The reason for this improvement is explained by looking at the temperature distribution at the bottom of the container which is heated by the burner. It appears that the movement of the maximum temperature towards the center of the bottom of the container improves the thermal efficiency. At the and, the effect of two parameters namely, the gas flow rate and the height of the container above the burner, are numerically studied and optimum values for these parameters are determined. Our numerical results show that the use of computational methods is a useful tool to study the performance of gas burners and improve their designs. Keywords: domestic stove burner, empirical research, computational fluid dynamics, thermal efficiency, combustion, burner geometry.