This study examines the portrayal of Syrians on Turkish Twitter between January and August 2021 through a big data analysis of more than 30,000 tweets. We employ the concept of online toxicity to differentiate between disinformation and hate speech and explore how they are embedded in the negative debates about Syrians on Twitter. Through opinion analysis, the study recognizes disinformation and hate speech patterns within tweets and questions the role they play in boosting anti-Syrian narratives, as well as the main actors behind them in the Turkish Twittersphere. The findings indicate that the discourse about Syrians on Twitter was overwhelmingly negative, with both disinformation and hate speech playing a significant role. Furthermore, a considerable portion of the disinformation tweets could be traced back to opposition political actors, highlighting how negative sentiment on Twitter was not only expressive of generalized public resentment against Syrians but also instrumentalized for political purposes. Overall, this article demonstrates how Twitter contributes to the public debate about Syrians in Turkey, reproducing nationalist narratives and serving political agendas.