Zoetis, Inc. (/zō-EH-tis/) is the world's largest producer of medicine and vaccinations for pets and livestock. The company was a subsidiary of Pfizer, the world's largest drug maker, but with Pfizer's spinoff of its 83% interest in the firm it is now a completely independent company. The company operates in 70 countries worldwide with recent expansions into Southeast Asia and China. Contemporaneous with the spinoff in June 2013 S&P Dow Jones Indices announced that Zoetis would replace First Horizon National Corporation in the S&P 500 stock market index.

In the 1950s, Pfizer began research on several drugs including Oxytetracycline. John McKeen, a chemical engineer with Pfizer products, discovered its effective use in livestock. In 1952, the Pfizer Agriculture Division opened a 732-acre research and development facility in Terre Haute, Indiana called Vigo. By 1988 the division was renamed Pfizer Animal Health.

The acquisition of GlaxoSmithKline’s Norden Laboratories in 1995 boosted Pfizer's animal health division into small animal care including domestic pets. Secondary research and development centres were opened in Kalamazoo, Michigan in 2003. In the same year, Pfizer acquired Pharmacia Corporation for US$ 60 billion in stock options. Between 2007 and 2011 the company acquired Embrex Inc, Catapult Genetics, Bovigen, Wyeth, Fort Dodge Animal Health, Vetnex Animal Health Ltd, Synbiotics Corporation, Microtek, King Pharmaceuticals, and Alpharma. These acquisitions greatly increased Pfizer's market, range of products, countries it operated in, and resources.

Plans to break away Pfizer Animal Health into a separate company were officially announced in 2012. The name chosen, Zoetis, roughly translates from the derived Latin zoological word zoetic, meaning 'pertaining to life'.

In 2011, Zoetis Inc.'s revenues exceeded $4.2 billion and $4.34 billion in 2012. The animal health industry worldwide is an estimated US$22 billion dollar industry.

On 22 May 2013, The Wall Street Journal reported that Pfizer plans to sell its majority stake in the company. According to the report, shareholders will have the option to swap their Pfizer shares for Zoetis shares. The sell off of Zoetis is consistent with Pfizer's recent decision to shed other non-pharmaceuticals subsidiaries in an effort to save costs, raise capital, and pay off debt. The company has announced that JPMorgan Chase, Bank of America Merrill Lynch, Goldman Sachs & Co., and Morgan Stanley will be the lead underwriters.

In November 2014, activist investor Bill Ackman disclosed that Pershing Square Capital Management had taken an 8.5% stake in the company, amassing approximately 41.8 million shares, causing the share price to hit its highest price since the IPO. On 17 November, the company announced it would acquire a portfolio of pet drugs from Abbott Laboratories for approximately $255 million.

In November 2015 the company announced it would acquire developer of aquaculture treatments and diseases, Pharmaq, for $765 million.

Records show that Pfizer officially filed for registration of a Class A stock with the U.S. Securities and Exchange Commission on 10 August 2012. Zoetis' IPO on 1 February 2013 sold 86.1 million shares for US$ 2.2 billion. Shares sharply rose 19% by the end of the trading day to $35.01 a share, up from $26. At the time, it was the largest IPO from a U.S. company since Facebook's $16 billion IPO on 18 May 2012. Pfizer retained 414 million Class B shares giving it an 83% controlling stake in the firm. Stock investors were attracted to the steep profit margin in proportion to revenue and consumer confidence in potential future growth of the subsidiary. The offering's lead underwriters were JPMorgan Chase, Bank of America Merrill Lynch and Morgan Stanley. Most of the money raised through the IPO was used to pay off existing Pfizer debt.

Twenty eight sites in 11 countries make up Zoetis manufacturing network, each facility designed to meet chemical and infectious agent safety regulatory requirements. Many R&D operations are co-located with manufacturing sites, a collaboration that allows to bring new products to market faster. Zoetis builds on six-decade Pfizer history and aims for high tech innovative manufacturing technologies. Zoetis products include: