Zopiclone (brand name Imovane in Canada, Australia and Zimovane in the UK) is a non-benzodiazepine hypnotic (a cyklopyrrolone, which increases the normal transmission of the signal substance GABA in the central nerve system, like benzodiazepines do, however in a rather different way) agent used in the treatment of insomnia. In the United States, zopiclone is not commercially available, although its active stereoisomer, eszopiclone, is sold under the name Lunesta (see History). Zopiclone is a controlled substance in the United States, Japan, Brazil and some European countries, and may be illegal to possess without a prescription.

Zopiclone is known colloquially as a "Z-drug". Other Z-drugs include zaleplon (Sonata) and zolpidem (Ambien and AmbienCR) and were initially thought to be less addictive and/or habit-forming than benzodiazepines. However, this appraisal has shifted somewhat in the last few years as cases of addiction and habituation have been presented. It is recommended that zopiclone be taken on a short-term basis, usually a week or less. Daily or continuous use of the drug is not usually advised. Zopiclone is a tranquilliser drug. It works by causing a depression or tranquillisation of the Central Nervous System. As zopiclone is sedating it is marketed as a sleeping pill. After regular dampening down of the Central Nervous System the body becomes accustomed to functioning under the influence of zopiclone. When the dose is reduced or the drug is stopped these adaptions which have occurred when a person's body has become addicted to a drug are revealed. The result is rebound withdrawal symptoms that can include a range of withdrawal symptoms seen in benzodiazepine withdrawal.