Although there are a lot of vegetables that are high in protein, tomatoes really are not one of them. The average raw tomato has around 1.29 grams of protein and chopped up it has about 1.80 grams.
Obviously the larger the tomato is the more protein it is going to have, though tomatoes that are chopped or diced have by far the most protein in them. This is something to consider when you are trying to get the most protein possible out of the tomatoes you eat.
Although by themselves tomatoes do not offer a ton of protein, chopped up they are a more significant source of it.