The buttocks are the two masses of muscle (gluteus maximus, sometimes abbreviated to "glute") and fat covering the posterior aspect of the human (primate) pelvis. They allow humans (primates) to sit upright comfortably without resting weight on their feet, as (for example) cats and dogs do when they sit upright.

They belong to the intimate parts. Exposing the bare buttocks as a protest or for fun is called mooning. Viewing a nice pair of buttocks of the desired gender is also sexually arousing for many, but not all. The sexual aesthetics of the buttocks vary greatly from culture to culture, with some finding leaner buttocks attractive while some find extremely fatty buttocks desirable.

In many cultures, corporal punishment is traditionally delivered on the buttocks (it is then called spanking). This is especially true for lighter punishment and domestic discipline on children (and in some cultures, on wives). Different reasons have been put forward to explain this:

• The buttocks are usually not exposed, making the punishment invisible to outsiders (and therefore making it difficult to prosecute cases of severe beating).
• The buttocks are considered shameful, and having to disrobe them for punishment is added humiliation in these cultures.
• While there are many nerve endings in the area (ensuring substantial pain), there is relatively little risk of the victim sustaining long-term injury since internal organs are unlikely to be affected.
• Some critics of corporal punishment see it as merely a sexual fetish, pointing to the well-documented spanking fetish as evidence, and the buttocks as intimate parts.

The anatomical Latin name for the buttocks is nates (pronounced in English), which is plural. The singular, natis, is rarely used.

Also See Gluteus Maximus