Forest Laboratories was an American pharmaceutical company headquartered in New York City. Forest Laboratories was known for licensing European pharmaceuticals for sale in the United States. The company had offices in St. Louis, Cincinnati, Jersey City, Oakland, Dublin, Kent and Paris.

In January 2014, Forest agreed to acquire Aptalis Pharma for $2.9 billion in order to gain access to treatments for gastrointestinal ailments and cystic fibrosis.

In February 2014, Actavis announced it would acquire Forest Laboratories for around $25 billion.

In April 2014, Forest announced it would acquire Furiex Pharmaceuticals for $1 billion in cash.

On July 1, 2014, Actavis (now Allergan, Plc, as of June 2015) completed its acquisition of Forest Laboratories.

Both Lexapro and Namenda are produced in bulk at the Forest plant in Dublin, Ireland, with secondary processing, such as bottling and blister-packing, being carried out in the U.S. at plants in New York and St. Louis.

Some of the products Forest Laboratories markets with its partners include:

In September 2010, Forest Laboratories, Inc. and Forest Pharmaceuticals, Inc. (a subsidiary of Forest Laboratories) agreed to pay more than US$313,000,000 to resolve allegations of civil and criminal liability relating to felony obstruction of justice and the illegal distribution and promotion of pharmaceuticals, charges to which it pled guilty. One of the pharmaceutical-related charges was a misdemeanor charge of illegally promoting the drugs Celexa and Lexapro for unapproved pediatric uses in treating depression. The other drug-related charge was a misdemeanor charge of distributing the unapproved drug Levothroid in violation of the Food, Drug, and Cosmetic Act (FDCA). Certain of the criminal activities were revealed with the help of whistleblowers, who were slated to receive US$14,000,000 from the federal component of the settlement.

On 13 May 2010, ABC news and Bloomberg business news reported that the organization "dodges taxes" by moving its profits offshore with the currently legal practice known as transfer pricing. U.S. Senator Carl Levin of Michigan has called transfer pricing "the corporate equivalent to secret offshore accounts of individual tax dodgers".