Add rolled oats, milk, yogurt, chia seeds, maple syrup, vanilla extract, and salt into a 16-ounce mason jar or equivalent airtight container.
Stir the mixture thoroughly with a spoon or secure the lid and shake vigorously until all ingredients are fully incorporated.
Ensure all oats are completely submerged in the liquid base to facilitate even hydration.
Seal the container with a lid and refrigerate for a minimum of 6 hours, or ideally overnight (8 hours).
Remove from the refrigerator and stir once more to redistribute any settled liquid before serving cold.