Contact your doctor in order to rule out medical conditions such as narcolepsy that can cause individuals to fall asleep. If you have a medical condition that is causing you to fall asleep in class, it will need to be treated by a professional. Prescription drugs may also cause sleepiness or drowsiness as a side effect, so discuss any medications you are taking with your doctor.
Get a full night's sleep on school nights. The National Sleep Foundation has reported that teenagers may need more sleep than adults. Go to bed earlier and make sure you get as many hours of sleep as your body needs. This is a key part to staying awake in class; if you are not tired, you are unlikely to fall asleep.
Eat a healthy breakfast full of nutritious foods that provide you with enough carbohydrates and protein to fuel your body. If you get hungry or tired in the middle of the day, try eating a healthy snack like a piece of fruit or some crackers. If necessary, drink something with sugar or caffeine in it directly before the class.
Get involved during class. If you are actively engaged in the information the teacher is presenting, you are less likely to doze off. Taking notes, asking questions and otherwise getting involved in classroom activities and discussions will make you far less likely to doze off.