Yes. You'll definitely need more calories than a woman carrying just one baby.
One rule of thumb is to add 300 calories a day for each of your babies. So if you're carrying twins, you should add roughly 600 calories to your normal load, which would probably take you to about 2,800 calories a day. If you're carrying triplets, you'd aim for an extra 900 calories a day, pushing your daily total to about 3,100 calories.