Preheat oven to 350, then line a 9" x 13" baking dish with parchment paper.
Mix together the graham cracker crumbs, melted butter, and sugar until thoroughly combined.
Spread evenly across the bottom of the dish using the bottom of a measuring cup, and press the mixture down firmly to form the crust.
Spread the sweetened condensed milk evenly over the prepared crust.
In a mixing bowl, combine peaches, chocolate, and flour and toss until coated.
Sprinkle evenly over the top, then bake on the center rack of the oven for 45 minutes.
Remove and let cool. For best results, refrigerate prior to cutting into bars and serving with your favorite topping. Enjoy!