Background: Dietary supplements are a term that refers to several products such as vitamins, minerals and high energy compounds. Using these supplements is very common among individuals in different communities. Pharmacists had important effect on the public health as they help individuals to choose supplements and provide them with information. Aim: To assess knowledge, attitude and practice of pharmacists toward dietary supplements. Methods: This study is cross sectional, it was conducted on pharmacists in Riyadh region, Saudi Arabia, using an online survey. Results: There were 500 pharmacists included in this study, 75.4% had good knowledge, 71.6% had positive attitude and 50.8% had good practice. Both of knowledge and attitude were significantly affected by age, experience years and level of education, whereas practice was significantly affected by experience years only (P-value˂0.05). Conclusion: There were good knowledge and positive attitude toward dietary supplements among pharmacists, however close percents had either good or bad practice.