Make the Crust: In a medium bowl, combine the graham cracker crumbs and melted butter. Press the mixture firmly into the bottom of a 9×13 inch baking pan.
Prepare the Filling: In a large bowl, combine the gelatin and boiling water. Stir until the gelatin is completely dissolved.
Combine: Stir in the sweetened condensed milk, orange juice, and orange zest.
Chill: Refrigerate for at least 2 hours, or until the filling is set.
Top: Top with the thawed whipped topping.
Chill: Refrigerate for at least 1 hour before serving.