This research, entitled “Legislative Problems in the Libyan Tax Legislation and Their Impact on Tax Evasion Cases”, examines how legislative shortcomings contribute significantly to the rise of tax evasion in Libya. The study reveals that Libyan tax legislation is characterized by rigidity and weak deterrent penalties that fail to effectively discourage tax evasion and ensure proper tax collection to sustain the state’s public treasury. The presence of loopholes in the current tax law allows taxpayers to evade their tax obligations. Notably, Law No. (10) of 2010 on Income Taxes largely repeats the same penal provisions found in earlier legislation without introducing substantial improvements The weakness of punitive measures has led to the emergence of groups that are difficult to handle fiscally, often operating within the shadow economy. Even those engaged in open economic activities are challenging to monitor due to the complexity and ambiguity of the law. Moreover, the legislation has not kept pace with modern developments, particularly with the rise of e-commerce, which has resulted in increased cases of tax evasion and double taxation. This, in turn, has burdened the state with accumulated tax debts. Additionally, the high and disproportionate tax rates have created further difficulties in law enforcement, especially amid the multiplicity and diversity of taxes. In contrast, many modern tax systems now tend toward imposing a general income tax to simplify their structures and facilitate monitoring—something the Libyan legislator has yet to adopt. Overall, this study highlights the vital role of taxation in enhancing and developing the state’s essential sectors through taxpayers’ compliance with their obligations. It also emphasizes that strengthening tax collection helps eliminate accumulated tax debts, improve international relations through administrative cooperation and information exchange, and increase public revenue while minimizing or eradicating tax evasion. Ultimately, the research calls for the creation of a modernized tax framework that aligns with the state’s economic and technological developments. Keywords: Legislative problems, Tax evasion, Weak deterrent penalties, Legislative loopholes.