Freeware and open source simulation software can be of great relevant when applying simulation in companies that do not possess the required monetary resources to invest in traditional commercial software, since these can be unaffordable Even so, there is a lack of papers that contribute to literature with a comparison of opensource and freeware simulation tools. Furthermore, such existing papers fail to establish a proper assessment of these type of tools. In this regard, this paper proposes a study in which several freeware and open source discrete-event general purpose simulation tools were selected and compared, in order to propose a ranking based on the tools’ popularity, considering several criteria. For this purpose, 30 criteria were used to assess the score of each tool, leading to a podium composed by SimPy, JSim and JaamSim. Further conclusion and future work are discussed in the last section.