The purpose of the article is to determine whether the guarantees of Article 6 of the ECHR in the form of the right to a fair criminal trial are available in juvenile proceedings, including in the welfare model. In addition, the goal was to examine what impact international standards have had on Polish law in this regard. The article uses the formal-dogmatic method and, to a limited extent, the legal-comparative method. The article shows that the right to a fair criminal trial guaranteed by Article 6 of the ECHR also applies in juvenile proceedings. Even in legislatures that adopt a welfare model, if the Engel test leads to the conclusion that the case is criminal in nature, the guarantees apply. The impact of Article 6 of the ECHR on the criminal law of individual countries is shown on the example of Polish legislation, presenting changes in Polish law as a consequence of ECtHR judgments.