Adipose tissue is a specialised connective tissue dominated by fat-storing cells called adipocytes. In humans it provides long-term energy storage, thermal insulation, cushioning around organs, and important endocrine functions through the release of signalling molecules called adipokines.

Most adult adipose tissue is white adipose tissue, in which each adipocyte contains a large lipid droplet that pushes the nucleus and cytoplasm to the cell edge. The tissue is also supported by a delicate network of connective tissue, blood vessels, immune cells, and nerves, reflecting its active role in whole-body metabolism rather than simply acting as passive fat storage.