In a jar or container with a lid, combine the rolled oats, milk (or yogurt), raspberries, white chocolate chips, and any additional sweeteners or flavorings.
Thoroughly stir all the ingredients together until they are well combined. Make sure the oats are fully submerged in the liquid.
Cover the jar or container with a lid and refrigerate for at least 2 hours, or preferably overnight. This allows the oats to soften and absorb the liquid.