Grate the cucumber using a box grater. Place the grated cucumber in a clean kitchen towel or cheesecloth and squeeze out as much liquid as possible. This prevents the sauce from becoming watery.
In a medium-sized mixing bowl, add the Greek yogurt, grated cucumber, minced garlic, fresh dill, olive oil, lemon juice, salt, and black pepper.
Stir all the ingredients together until well combined.
Cover the bowl and refrigerate the tzatziki sauce for at least 30 minutes to allow the flavors to meld together.
Enjoy as a dip, sauce, or spread with your favorite Mediterranean dishes.