Tesco Corporation (Tesco) is an oilfield services company specializing in the design, manufacture and service of technology-based solutions for the upstream energy industry. Its headquarters are located in the Spring Branch district of Houston, Texas, United States.

On August 14, 2017, it was announced that Nabors Industries agreed to acquire Tesco Corporation in an all-stock transaction.

Tesco was created in December 1993 when Shelter Oil and Gas Ltd., Coexco Petroleum Inc., and Forewest Industries Ltd. merged as Tesco Corporation, originally Tesco Drilling Technology, a joint venture between the three. Tesco originally became famous for inventing the first portable land top drive, which won a Special Meritorious Award for Engineering at the 1994 OTC show. Since then, Tesco has branched out into casing running as well, including a casing running tool called the Casing Drive System, or CDS. In 2006, the company moved their headquarters from Calgary, AB to Houston, TX, while continuing to manufacture in Calgary.

On 30 April 2012, Tesco and Schlumberger announced a deal in which Tesco's CASING DRILLING™ division would be sold to Schlumberger for $45 million in cash.

Tesco provides top drive rental services on a day-rate basis for land and offshore drilling rigs and after-market sales and service for its customers. Tesco’s top drive rental fleet comprised 132 units on December 31, 2011. In order of size by region from highest to lowest, Tesco currently has rental units in Latin America, the United States and Canada, Russia, Asia-Pacific, Europe, and the Middle East. In response to the economic downturn and operating conditions during 2009, Tesco redeployed over 10% of Tesco’s U.S. fleet to international locations, including the Middle East, Latin America, Russia and Asia. Tesco's major competitors in the top drive market include National Oilwell Varco, Canrig, a subsidiary of Nabors, and FDS.

Similarly, Tesco provides conventional and proprietary casing running services. The company operates both conventional equipment and a proprietary casing running tool, the Casing Drive System, for rigs equipped with top drives. These technologies were originally developed for CASING DRILLING™, but were discovered to be useful on their own. In addition, several other accessories packages are available. Other companies operating in the same sector include National Oilwell Varco, Franks International, Canrig, and Weatherford International.

List of oilfield service companies