Recent advancements in generative pre-trained transformers (GPT) allowed for the production of text that is almost indistinguishable from human-written content, introducing a number of unprecedented challenges to the academic environment, particularly academic integrity. Various online tools claim to be able to distinguish AI-generated from human-written text. This thesis will follow up on a study “Testing of Detection Tools for AI-Generated Text” (Weber-Wulff et. al, 2023). It will closely examine how GPT models and AI-detection tools work. It will design a clear methodology, choose tools that will take part in the testing, create a new evaluation dataset and by using various metrics assess how effective detectors are at evaluating content written in Czech and Slovak compared to English.