In a medium bowl, mix together oats, milk, pumpkin, pumpkin pie spice, cinnamon, vanilla, and honey. Pour into two mason jars or an airtight container with lid.
Refrigerate for at least 4 hours, or preferably overnight, so that the oats will soften and absorb the liquid.
Remove from refrigerator, stir, and top with crushed graham crackers, if desired.