In a large zip-top bag (or mixing bowl), combine the plain Greek yogurt, lemon juice, olive oil, garlic, dried oregano, cumin, coriander, salt and pepper. Squeeze the bag or whisk to mix.
½ cup plain Greek yogurt, 6 tablespoons fresh lemon juice, ¼ cup olive oil, 4 cloves garlic, 1 tablespoon dried oregano, 2 teaspoons ground cumin, 1 teaspoon ground coriander, 1 teaspoon salt, ½ teaspoon black pepper