Heat pipes are heat transfer devices that utilize phase change mechanisms to carry high amounts of heat with low temperature differences between two reservoirs. Due to this main advantage over conventional methods, heat pipes are popular in numerous industrial applications, particularly electronics cooling. Parallel to increasing number of applications, modelling techniques and predicting the thermal performance of heat pipes having different geometries became an important issue. In this study, in order to understand the effect of the groove and fin width variation for the same groove pitch value, a parametric performance analysis is conducted for a wide range of groove and fin widths. Heat transfer and the phase change mechanisms of working fluid are modeled using thermal resistance network for the flat grooved heat pipes. Temperature and contact angle differences between two ends of the heat pipe are used as the performance parameter for the better understanding the effect of the investigated parameters.