Since the early 2000s, the European Union evolved a policy of externalization of management of migration into its territory. The externalization policy makes migrant transit countries neighboring the EU a frontier of EU migration control. As a significant jumping-off point of the Central Mediterranean Route for EU-bound migrants, and given its weak state structure, Libya is a fundamental component of the EU externalization policy. In enforcing the EU externalization policy through EU-funded and supported interception and detention of EUbound migrants, Libya's authorities have systematically abused migrants. This study examined the responsibility of the European Union for the abuses of migrants in Libya. The study relied on the theory of state responsibility to argue that the EU is responsible for the abuses of migrants by Libyan authorities pursuant to the implementation of the EU externalization policy. This study is a single case study that relied on content analysis to make inferences from the corpus of documents retrieved mainly from EU institutions and international human rights organizations' reports. The result shows that the EU relied on cooperation agreements like the Memorandum of Understanding 2017 and the Malta Declaration 2017 to train Libyan Coastal security, provide logistics, share information on migrants’ boats, and fund the interception, detention, and abuse of thousands of migrants by Libyan authorities. Considering the weak state institutions in Libya, the abuse of migrants in Libya, and the responsibility of the EU to immigrants under its own laws and international conventions, the study recommends that the European Union reassess its engagement with Libya in the area of migrants’ interception and detention, with a view to providing for migrants detention in the EU where their rights are more recognized.