It depends... It is high in calories and if you don't count it as a food, the extra calories could pack on. If it has extra sugar, it will be even higher in calories and will raise blood sugar. If it is pulp free, there basically isn't any nutritional value other than vitamin C. It depends what kind you drink, and how much.
According to the show, "The Doctors," produced by Dr. Phil, orange juice has a lot of sugar which is not good for your heart. It would be better to eat an orange because the fiber is good for you digestive track among other things. Orange juice does not have fiber. I do not believe orange juice will make you fat.