Disinformation is not a new phenomenon, but it is widespread in our society since social media have become a media loudspeaker. The outbreak of war in Ukraine has produced a social debate, partly reflected on social networks, about the treatment of Ukrainian refugees compared with other refugees from the South. For this reason, this research proposes a study that follows a qualitative interpretative methodology with an exploratory and descriptive scope that analyses in depth the content of the discourse on Twitter about refugees and uses computer-mediated discourse analysis as a technique for obtaining data. Specifically, it compares the content published under the hashtags #NotRefugees and #Refugees, and for this purpose, a data analysis has been carried out using Atlas.ti. The results show a differentiated treatment between refugees from the North and the South, as well as a propagation of misinformation through hate speech, in which a favourable and welcoming treatment of Ukrainian refugees is shown, while various types of hate speech towards the rest of the refugees from the South are evident. Hate towards refugees from the South on Twitter is justified on the grounds that they threaten national security, economy, and identity. This phenomenon reflects the urgent need to develop critical and ethical digital competence in the face of disinformation in social networks and media, where the development of critical and ethical thinking is essential.