Preheat the oven to 350 degrees F (175 degrees C).

Combine graham cracker crumbs, sugar, and melted butter in a bowl; mix to combine and pat into the bottom of a 9x13 inch baking pan. Bake in the preheated oven for 15 minutes. Keep the oven on.

Combine condensed milk and flaked coconut; spread over the crust and continue to bake for 15 minutes.

Spread melted chocolate over coconut layer. Set aside to cool and let chocolate harden, about 1 hour. Cut into squares.