Below is a list of the largest nebulae so far discovered, ordered by size. This list is prone to change because of inconsistencies between studies, their great distances from our stellar neighbourhood, and constant development of technology and engineering. Nebulae's boundaries are also undefined, and is also prone to change. Lastly, scientists are still defining the parameters and defining features of nebulae. Because of all these scientific inconsistencies, this list might be unreliable.