Preheat the oven to 350°F. Line a baking sheet with a parchment or silicone liner. Open the crescent roll package and separate the rolls into eight triangles.
In a small bowl, whisk together the cinnamon and sugar. Dip each of the marshmallows in the melted butter, then roll in the cinnamon sugar mixture.
Place a marshmallow in the middle of each dough triangle, then roll the dough tightly around the marshmallow, pinching to close all of the seams.
Place the rolls on the prepared baking sheet. Bake for 10-14 minutes, or until golden brown.