Tobacco use is considered as one of the leading causes of lung cancer and Chronic Obstructive Pulmonary Disease (COPD). The use of tobacco is dependent upon many factors, such as age, sex, social class, education and income. Therefore, the trend of tobacco consumption is shifting from the developed to the developing countries. The purpose of this study was to identify the contributing factors which lead to tobacco use among undergraduate university students (18-25 years). A retrospective Case-Control study was carried out on 560 (280 Cases and 280 Controls) undergraduate students in three universities of Khyber Pukhtunkhwa (KP), Pakistan. Data was collected through a self-filled structured questionnaire, which was analyzed using descriptive and inferential Odd Ratio (OR) statistics, via SPSS Version 19. The data revealed that tobacco use is significantly associated with brothers (OR: 1.81), and other family members (father in law, grandfather, nephew, relatives) (OR: 3.62) who are addicted to tobacco use. Tobacco using friends (OR: 15.39), use of tobacco in university (OR: 4.37), hostel (OR: 3.79), and public places (OR: 1.49) are also significantly associated with tobacco use. Staying in social gatherings (OR: 2.23) where people use tobacco and offer it to others (OR: 7.43) is also linked with tobacco use. Getting impressed by media promotion advertisements (OR: 1.81), and beliefs about the beneficial effects of tobacco use (OR: 2.19) are also significantly related to tobacco use. Furthermore, having personal problems (OR: 1.78), physical / medical diseases (OR: 1.78), and financial problems (OR: 1.57) were also found significantly associated with tobacco use. The study concluded that there are many factors like tobacco using family members, peer pressure, social gatherings where tobacco is used and offered freely, and promotion of tobacco by media, etc., are positively associated with tobacco use among undergraduate university students (18-25 years) in KP, Pakistan.