This research aimed to explore gender differences in nutritional, odontological and psychological patterns of adolescent students during the COVID-19 pandemic. In order to achieve the study’s aim, 127 adolescent students (17.61 ± 7.43 years) completed an online questionnaire which analysed variables regarding their psychological, nutritional, oral health, and physical activity profiles and habits during the COVID-19 crisis. Students showed a higher weekly alcohol consumption and higher levels of loneliness perception when alcohol consumption was lower. In addition, experimental avoidance and psychological inflexibility values were lower when the perception of having dry mouth or lack of saliva is higher. The results also show that males presented a more varied intake of food than females and a stronger adherence to physical activity routines. Female students presented a lower number of meals per day when beer and alcohol consumption was higher, and a higher tendency for fat- and sugar-rich foods such as fast food or bakery products than males. Regarding the oral health profile, females showed higher values in daily tooth brushing and no significant differences were found in dry mouth and gastritis variables. The results from the present study could be used by various educational institutions to implement multidisciplinary interventions to develop healthier habits.