Background: Admission to the university is a new stage of life for students that are generally associated with independence, social activities, and changes in lifestyle and behavior including changes in nutritional habits. Objectives: The study objective was to investigate the lifestyle and major dietary risk factors associated with the development of overweight and obesity among Najran University students, Saudi Arabia. Materials and Methods: 300 undergraduate students attending Najran University completed a self-administered questionnaire on demographic, social, and cultural data, as well as information on eating habits, health and nutritional status. The questionnaire was labeled and coded by the researcher. The data obtained were subjected to analysis using Microsoft Office Excel 2007. Results: Analysis of the dietary habits of the students in the present sample revealed adoption of several undesired dietary habits. Two-thirds of them had between 1 and 2 weekly servings of fruit and vegetables, more than half choosing the less healthy food, fast food in particular, and about one-third only having a regular healthy breakfast on a daily basis. Almost two-thirds (62%) of the students have normal body mass index, almost 14.2% are underweight, 11% are overweight, and 12% are obese. 29% of the students engaged in regular exercise while another 25% stated that they never or hardly ever perform physical exercise. Most students, about 40% go to bed between 1 and 3 am, 47% sleep for <6 h/day, and more than 50% feel that they are not getting enough sleep although 24% always take a nap and 45% take a nap occasionally. Majority of the students did not smoke, with 17.2% of the students being regular smokers. These figures reflect the rather unhealthy dietary and lifestyle patterns of Najran University students in general. Conclusion: This study showed the difficulties that university students encounter, especially when they are away from the family, in following a healthy lifestyle and taking care of themselves from the nutritional point of view. The present data had shown relatively alarming prevalence of overweight/obesity, unhealthy dietary practices, and lifestyle behaviors that should be targeted and modified. This project provides valuable data that could be used by policymakers to address issues concerning students' health.