Background: Adverse drug reactions (ADRs) are one of the major reasons of morbidity and mortality all over the world. The knowledge of ADRs is essential for healthcare professionals as they are in contact with the patients and can effectively detect the ADRs. Purpose of the study: To evaluate the knowledge, attitude, and practice of pharmacovigilance in healthcare professionals and medical students in Majmaah, KSA. Methods: This was a crosssectional questionnaire-based study. The health care professionals of Al-Majmaah, i.e., doctors, nurses, pharmacists including the medical students were included in the study. Results: Total 148 participants were included in the study, 89% of these were male and 11% were females. Overall the knowledge and awareness regarding pharmacovigilance and ADRs was low ranging from 27% to 64.2%. There was a consensus among the healthcare professionals including the medical students that reporting of the ADRs is necessary and it should be taught in detail to them denoting a positive attitude. Overall reporting rate for ADRs was only 35.1% even though the percentage of professionals who encountered the ADRs was 52.7%. Conclusion: Findings of this study point us towards an important aspect of medicinal safety that is lack of knowledge about the adverse drug reactions and their reporting in doctors, nurses, pharmacists, and medical students. The lack of knowledge also reflects on their practice of not reporting the ADRs adequately.