The article deals with legal gender from the conflict-of-laws perspective. Its aims are: to identify the law applicable to the establishment (upon birth) and change of legal gender under Polish private international law, to determine that law’s scope of application, and to indicate the values that should be taken into account when considering the intervention of the ordre public. Given the gap existing in Polish PIL in matters of legal gender, the applicable law should be searched for on the basis of a generic rule of art. 67 of the Polish PIL Act. In my opinion, under that rule, it is the national law of a person that should be considered to be the law applicable to that person’s legal gender. However, the establishment or change of legal gender that occurred abroad may be qualified as “a closed legal situation.” Thus, the law determined by the relevant rule of that situation’s state of origin may be deemed the applicable one. The laws applicable to the potential impact of the legal gender’s change on marriage, name and surname, filiation and succession should be searched for separately. If the change of legal gender is inadmissible under the applicable law, the public policy exception may be used in order to allow such change, based on the individual’s right to respect for their sexual self-determination, which is one of the aspects of the right to respect for private life under the ECHR. However, the decision to apply the public policy exception should always be preceded by an assessment in concreto. This also concerns dealing with a foreign rule that provides for “the third gender” being assigned to a child. The child’s best interests and the values related to the cross-border continuity of a personal legal status should be taken into account in this regard.