Background: This study examines stigma and self-stigma towards individuals with intellectual disabilities among university students, focusing on cognitive, emotional and behavioural dimensions. It highlights the negative impact on social inclusion and the importance of educational interventions. Methods: A quantitative pre-/post-test design with a control group assessed stigma towards intellectual disabilities. Differences based on the presence of intellectual disabilities and the effectiveness of an anti-stigma intervention was evaluated using the Goratu questionnaire. Results: No significant gender differences in stigma levels were found. Students with intellectual disabilities showed significantly higher stigma levels compared to their peers without disabilities. The anti-stigma intervention improved attitudes in the experimental group versus the control group. Conclusions: Findings support the efficacy of educational interventions in reducing stigma and promoting inclusive attitudes. Despite limitations like potential social desirability bias, this research offers valuable insights for policymakers and educators to enhance social inclusion and reduce stigma.