Pour the oyster crackers into a gallon size zip-top bag.
In a small bowl, combine the ranch dressing mix and garlic powder then pour into the bag along with the vegetable oil. Close the bag and shake to coat the crackers in the mixture.
Set the bag aside to rest for 30 minutes so the crackers soak in the oil and seasoning.
Preheat oven to 250F.
Spread the seasoned crackers out in an even layer over two baking sheets. Bake at 250F for 20 minutes until golden brown.
Cool the crackers completely to room temperature before serving.
Notes
To make the crackers spicy, add 1-2 tablespoons crushed red pepper
Store the leftover crackers in an airtight food storage container at room temperature for up to 2 weeks.