Liposuction, also known as lipoplasty ("fat modeling"), liposculpture or suction lipectomy ("suction-assisted fat removal") is a cosmetic surgery operation that removes fat from many different sites on the human body. Areas affected can range from the abdomen, thighs, buttocks, to the neck, backs of the arms and elsewhere. The fat is usually removed via a cannula (a hollow tube) and aspirator (a suction device).

Liposuction is not a low-effort alternative to exercise and diet. It is a form of body contouring with significant attendant risks and is not a weight loss method. The amount of fat removed varies by doctor, method, and patient, but is typically less than 10 pounds (5 kg).

There are several factors that limit the amount of fat that can be safely removed in one session. Ultimately, the operating physician and the patient make the decision. There are negative aspects to removing too much fat. Unusual "lumpiness" and/or "dents" in the skin can be seen in those patients "over-suctioned". The more fat removed the higher the surgical risk.

While reports of people removing 50 pounds (22.7 kg) of fat are exaggerated, the contouring possible with liposuction may cause the appearance of weight loss to be greater than the actual amount of fat removed. The procedure may be performed under general or local ("tumescent") anesthesia. The safety of the technique relates not only to the amount of tissue removed, but to the choice of anesthetic and the patient's overall health. It is ideal for the patient to be as fit as possible before the procedure and to have given up smoking for several months.