It was once believed that vegetarians had to combine foods at each meal in order to receive enough essential amino acids (building blocks of protein), but if a mixture of protein is consumed throughout the day enough will be provided. As long as a person consumes enough calories to maintain their weight and eats a varied diet they can easily meet their protein needs on a vegetarian diet. 

Animal derived vegetarian sources of protein include:

Eggs Milk
Greek yogurt Cheese



Vegetarian sources of protein include: 

Beans Lentils Nuts and Seeds
Quinoa Tempeh Hummus
Seitan Tofu Peas