The novelty of financing of terrorism offense and the extent of its seriousness and effects on society and the economy has interested the research to conduct this study. The study aims to discover how the Omani legislator dealt with this offense, by analysis the povisions of the Law of Anti-mony Laudering and Terrorism Fainancing (Royal Decree No. 30/2016), and comparing these provisions to the previous law (Royal Decree No. 79/2010), both Arab and Westerns legislations and international conventions. Therefore, the research subject discusses financing of terrorism offense in the Omani and Comparative Law. The research is divided into three chapters. First, the introduction covers the definition of terrorism financing offense and it stretches in two parts. One part gives the dictionary, legal and doctrinal meaning of this offense. The second segment gives room for the legal nature of the offense being researched and its characteristics Furthermore, the researcher highlights the phases and sources of financing terrorism in the first chapter which comes in two points. In one hand, the research analyses the phases of financing terrorism and its indicators. On the other hand, the researcher handles the sources of financing terrorism both legitimate and illegitimate sources. As for the second chapter, the study speaks about the element of financing terrorism offense ant its punishment. Hence, the researcher puts these two concepts in two separate thoughts. First, the author clarified the elements of financing terrorism offense. The second point shed lights on the potential punishment that the terrorism financier faces. Eventually, the researcher concluded the study with the findings and consolidated them with some recommendations with the hope such recommendations to be taken into consideration by the legislative authority in Oman if there is a tendency toward amending the legal frame of counter terrorism and its financing sources, the researcher, in addition, hopes that the study can contributes in the efforts of countering the terrorism financing.