Witnesses testimony is considered is considered type evidence upon which the judiciary relies in criminal lawsuits, leading to the formation of the judge's conviction and the issuance of a relevant judgment. Sometimes, it may be the only evidence to prove the crime charged against the accused. Therefore, various legislations have sought to regulate provisions for the protection of witnesses and those in their custody, such as informants, experts, and victims, even extending to the protection of their families, encouraging witnesses to contribute to achieving justice without fear of perpetrators’ threats or harm. Accordingly, this study aims to identify the legal framework for such protection, along with determining the position of Omani legislator, given its importance in highlighting the necessity of Omani legislation regulating provisions for the protection of witnesses and those in their custody in the Sultanate of Oman. The study adopted a descriptive analytical approach to describe the details of the modern legal system related to the protection of witnesses and those in their custody, analyzing some relevant legislations to determine the position of Omani legislators. Additionally, a comparative method was employed by comparing Omani legislations related to the study's topic with UAE applicable legislations, in order to answer the research question, which is: How effective is Omani legislation regarding the protection of witnesses and those in their custody? Consequently, the study concluded that Omani legislation has stipulated some measures related to the first type of protection, which is objective criminal protection. However, as of the writing of this thesis, it has not included any provisions related to establishing procedural (formal) protection م measures for witnesses and those in their custody (except for the provision regarding providing necessary protection for the victim or witness whenever needed, as stated in the Anti-Human Trafficking Law). The study ended with a recommendation that Omani legislator should issue an independent law containing all provisions related to the protection of witnesses and those in their custody, or amend the effective Criminal Procedure Law by adding a special chapter relating to the same subject matter. Keywords: Witnesses, informants, witness objective protection, witness procedural protection.