Dust bunnies or dustbunnies are balls of material which collect underneath furnishings, where people often have trouble cleaning. A typical dust bunny includes hair, dust, lint, scraps of various fibers, dead skin, and sometimes things like feathers, paper, and small objects which may have become caught up in the dust bunny. Dust bunnies are so well known that they even have their own pop culture references, and it is even possible to find guides to the care and feeding of dust bunnies on various websites, poking fun at the idea of dust bunnies as living organisms.

While some people dismiss dust bunnies as harmless, they can in fact be troublesome. For one thing, they wreak havoc on electronics if they are allowed to accumulate, because they can clog vents, causing the electronics to overheat. Dust bunnies can also clog things like vacuums if they get especially large. Furthermore, dust bunnies harbor dust mites, which can cause allergic reactions and respiratory problems.

Dust bunnies tend to gather under low, heavy furnishings. The height of such furnishings makes it difficult to see under them, thereby obscuring how dirty the floor underneath them is, and making it hard to clean under them as well. The weight makes it challenging to move such furnishings, so only the most dedicated cleaners will shift them to sweep, mop, or vacuum underneath, and even then, the furniture may rarely be moved.

The substances in dust bunnies are held together through felting, and static electricity. As static charges build up, dust bunnies can even become attracted to each other, creating a sort of super dust bunny which is extremely large. In households with lots of pets or humans with long hair, dust bunnies can get very large and very entangled, making them unpleasant to encounter.

Many people only notice dust bunnies when they move out, or when they replace a piece of furniture, although they may be aware that dust and dirt are probably skulking under large pieces of furniture. Because dust bunnies can cause health problems and hinder the operation of electronics, it's a good idea to make a plan to clean them out on a regular basis; for example, all the furniture in a room could be moved every six months for cleaning to get rid of dust bunnies. It also possible to find cleaning tools designed for dust bunnies, like wand attachments for vacuums and cleaning rods which can fit under low furnishings.