Background: Regardless of attaining adequate knowledge regarding oral hygiene, physical activity, and healthy eating habits, dental students still face oral health problems. This study was aimed to assess the association of oral hygiene habits, physical activity, and eating habits with the BMI in the dental students. Method: This multi centric cross-sectional study was conducted from January to May 2021 in Pakistan. Three hundred and eighty-six study participants enrolled as undergraduate dental students, both males and females, were included in the study. A questionnaire used to gather data, was modified from a study conducted by Jouhar et al. Chi-square testing was used in order to assess the relationship between two categorical variables. Linear regression was performed to assess the association with putative confounders. Statistical significance was considered for p value < 0.05. Results: Regarding brushing teeth, 57% of the underweight individuals brushed once daily, 69.8% of the healthy, 79.2% of overweight, and 48% of obese participants brushed twice. Horizontal brushing technique was performed by 50% of the underweight participants, followed by scrub technique. A soft bristled brush was frequently used by underweight (42.9%) and healthy (66%) individuals, while a medium textured bristle brush was used by overweight (62.3%) and obese (54.2%) participants. Majority of the underweight (64.3%), overweight (48.1%), and 45.8% of obese individuals had meals thrice a day, while healthy (62.3%) individuals had meals twice a day. Conclusion: This study further intensified the contributing role of having an excessive dietary intake and sugar consumption in causing obesity and dental caries. Findings from the current study, identify a statistically significant relationship that exists between BMI levels with oral hygiene, eating habits and the physical activity.