Combine okra, tomato, and onion in a large bowl. Add grits, eggs, salt, and pepper and mix with your hands until well blended. Shape the mixture into 2 1/2-inch-wide patties, about half as large as a hamburger.

Heat oil in a cast iron skillet over medium-high heat. Add fritters and cook until golden brown, about 5 minutes. Flip with a spatula and cook until browned on the other side, about 5 more minutes. Drain on paper towels and serve immediately.