Place almond milk, pumpkin puree, maple syrup and pumpkin pie spice in a 32-ounce mason jar or large container. Seal and shake well to combine. If using a container mix well with a whisk. Add oats and stir to evenly combine.
Seal and refrigerate overnight or until oats are softened. Enjoy within 3 or 4 days, may heat before serving if desired.