Aim: To assess the knowledge and awareness of undergraduate dental students at King Saud University (KSU) about oral cancer. Materials and methods: A cross-sectional study was conducted based on a questionnaire containing 21 questions about prevention, clinical aspects, history taking, knowledge of risk factors, and changes related to oral cancer. One hundred fifty undergraduate dental students were enrolled. Statistical analyses were conducted using Statistical Package for the Social Sciences (SPSS) 24 software. Results: It was shown that of 150 respondents, above 95% of the dental students considered smoking and alcohol consumption as the main risk factor for oral cancer. Squamous cell carcinoma was described as the most common type of oral cancer by 78% of the students. Clinical changes of oral cancer were acknowledged well by dental students (52.6% erythroplakia and nonhealing ulcer 65%). Only 41.4% of students have reported that they consider oral cancer during dental examination in the first appointment. Conclusion: Most of the students have a good level of awareness related to oral cancer, however an inadequate level of knowledge about the clinical features of oral cancer is present. Therefore, it is suggested that reinforcement of knowledge is recommended throughout the undergraduate dental course to enable improved early detection and diagnosis of oral cancer.