Purdue Pharma L.P., formerly the Purdue Frederick Company, is an American privately held pharmaceutical company founded by John Purdue Gray. It was owned principally by members of the Sackler family as descendants of Mortimer and Raymond Sackler. In 2007, it paid out one of the largest fines ever levied against a pharmaceutical firm for misleading the public about how addictive the drug OxyContin was compared to other pain medications. Although the company shifted its focus to abuse-deterrent formulations, Purdue continued to market and sell opioids as late as 2019 and continued to be involved in lawsuits around the opioid epidemic in the United States. Purdue filed for Chapter 11 bankruptcy protection on September 15, 2019, in New York City.

On October 21, 2020, it was reported that Purdue had reached a settlement potentially worth US$8.3 billion, admitting that it "knowingly and intentionally conspired and agreed with others to aid and abet" doctors dispensing medication "without a legitimate medical purpose." Members of the Sackler family will additionally pay US$225 million and the company will close. Some state attorneys general protested the plan. In March 2021, the United States House of Representatives introduced a bill that would stop the bankruptcy judge in the case from granting members of the Sackler family legal immunity during the bankruptcy proceedings. In September 2021, Purdue Pharma announced that it would rebrand itself as Knoa Pharma.