Since the beginning of Russia’s invasion of Ukraine on 24 February 2022, the Ukrainian authorities have faced an unprecedented surge in the numbers of alleged mass atrocity crimes committed in the areas of hostilities and parts of Ukraine’s (de)occupied territories. Eight months into the war, the Office of the Prosecutor General of Ukraine has already registered over 47,000 instances of alleged crimes, including war crimes and the crime of aggression. Ukrainian courts have swiftly delivered first verdicts in the war crimes trials signalling their willingness to deliver justice even in the midst of the raging war. This article provides a brief recap of the domestic prosecution of atrocity crimes prior to Russia’s invasion of Ukraine on 24 February 2022. It then evaluates the progress that has been achieved by the Ukrainian authorities and judiciary in relation to the prosecution and adjudication of war crimes since the beginning of Russia’s invasion of Ukraine. It analyses key findings of the first war crimes verdicts rendered by the Solomyanskyy District City Court in Kyiv (later modified by the Kyiv Court of Appeals with respect to the sentence) and the Kotelevskyy District Court in the Poltava region, and appraises the application of international humanitarian law by Ukrainian judges. The article concludes by situating Ukrainian domestic efforts within the larger context in closing the impunity gap for atrocity crimes against the backdrop of a broader discussion of transitional justice in Ukraine.