Gather all ingredients.
Whisk mayonnaise, ketchup, and garlic powder together in a bowl. Add Worcestershire sauce to the mayonnaise mixture and whisk until smooth.
Sprinkle enough pepper over the surface of the mayonnaise mixture to cover; stir to incorporate. Repeat sprinkling and stirring of pepper once more.
Cover bowl with plastic wrap and refrigerate until the seasonings have blended into the sauce, at least 2 hours.
