The prevalence rate of vitamin D deficiency over the last decades has grown up rapidly worldwide among young adults. Therefore, the aim of this study is to explore the knowledge, attitude, and practice of Libyan medical students of Sebha University regarding vitamin D deficiency. Out of a total of 200 questionnaires, 148 completed questionnaires were returned (74.0% response rate). The majority of respondents did not measure their vitamin D levels (62.1%). Participants who indicated they were exposed to sunlight for less than 15 min were 47.2% while 74.9% were exposed to less than 30 min with a highly significant gender difference (p<0.001). All the males did not use sunscreen creams compared with females (43.5%). Nearly two-thirds of the participants (61.4%) denied drinking milk almost daily with significant differences based on gender (p<0.005) while 56.0 % of the participants reported eating fish, 60.8% of the students denied eating fast food and 74.3% eating eggs daily or weekly. However, 49.3% of the students usually drink tea and coffee after meals, and do not usually practice exercise (53.3%), however, disagreed that their food has a low amount of calcium (30.4%). Most of the students agreed with the benefits of vitamin D (72.0%). Based on the assessment of awareness of the participants about vitamin D information, the average of correct answers percentage of the respondents was 47.1%. The most frequent sources of vitamin D information were the internet which accounted for 49.3%, followed by relatives and friends (31.7%). Some of the respondents (58.7%) reported that unawareness is the main cause of vitamin D deficiency. This study highlights the lack of awareness about the importance of vitamin D among medical students. This finding provides the institutions of medical education in Libya with an evidence base for a deficit of knowledge regarding young health which could be utilized to draw a strategy to correct the health behaviors of students and the community through medical education programs.