This study aims to clarify the law applicable to eligibility issues in light of the existence of legal relations with a foreign element, in which problems arise regarding knowledge of the law that determines the age of eligibility and the rights resulting from it, in the light of the Palestinian legislation in force, while comparing it with some Arab legislation such as Jordanian, Algerian and Egyptian In addition to relying on the opinions of jurists and court rulings, by clarifying what is meant by capacity, which is one of the characteristics closely related to a person, which is meant by the authority by which the extent to which a person is able to enjoy rights, bear obligations and the ability to carry out legal actions, as well as clarifying the rule of attribution of capacity. Most of the legislations tended to subject them to the nationality law because of the stability and stability of this law, which prevents the creation of a troubled legal status for people every time a dispute related to capacity is raised before the judiciary, and it was also clarified that what is meant by capacity in the rule of attribution is the capacity to perform without Obligatory capacity, the capacity to perform is linked to the person’s will and is affected by discrimination and the age of majority, as the legislation in question has linked the age of majority to the age of majority. Specific, unlike the Code of Judicial Judgments, which contented itself with setting a specific standard, and left it to the judge to research each case separately. As for the eligibility of the obligation, it is linked to the right to be enjoyed, which in turn leads to a difference in the law that will govern the eligibility of the obligation according to the difference of the right to be enjoyed. Highlighting the most important exceptions to the rule of attribution of eligibility, which most countries tended to adopt in their laws.