- Rabobank – Raiffeisen-Boerenleenbank (Dutch for Farmers Loan Bank), a combination of the two cooperatives that merged to form the company.
- RAND – Research ANd Development.
- Raytheon – "Light of the gods". Maker of missiles such as Patriot, Maverick, Sidewinder and Tomahawk, among other military technology.
- RCA – Radio Corporation of America.
- Reckitt & Colman – named from the merger of Reckitt & Sons with J&J Colman in 1938. Colman's, best known for its mustard, was founded by Jeremiah Colman in 1814. Isaac Reckitt founded Reckitt & Sons in 1840.
- Reckitt Benckiser – consumer goods giant named from the merger of Britain's Reckitt & Colman and the Dutch company Benckiser NV in December 1999. The latter was named after its founder, Johann A. Benckiser.
- Red Hat – while at college, company founder Marc Ewing was given the Cornell lacrosse team cap (with red and white stripes) by his grandfather. People would turn to him to solve their problems and he was referred to as that guy in the red hat. By the time he wrote the manual of the beta version of Red Hat Linux he had lost the cap, so the manual included an appeal to readers to return his Red Hat if found.
- Reebok – alternate spelling of rhebok (Pelea capreolus), an African antelope.
- Renault – French car manufacturer founded in 1899 as Société Renault Frères (French for Renault Brothers) by Louis Renault and his brothers Marcel and Fernand.
- REO Motor Car Company – car manufacturer founded in 1904 by Ransom E. Olds, and named from its founder's initials. Later, the rock band REO Speedwagon took its name from one of its trucks, the REO Speed Wagon.
- Repsol – name derived from Refinería de Petróleo de eScombreras Oil (Escombreras is an oil refinery in Cartagena, Spain) and chosen for its euphony when the, then, state-owned oil company was incorporated in 1986. Previously Repsol was a lubricating-oil trademark.
- Research In Motion – from the phrase "poetry in motion", which company founder Mike Lazaridis had seen used to describe a football player.
- Rickenbacker – named after co-founder Adolph Rickenbacher, with the spelling anglicised. The company started as the Electro String Instrument Corporation in 1931.
- Robeez – baby-shoe company named after the founder's son Robbie (Robert). Robeez was taken over by Stride Rite in 2006.
- Rolls-Royce – name used by Rolls-Royce plc and Rolls-Royce Motor Cars, among others. In 1884 Frederick Henry Royce started an electrical and mechanical business, making his first car, a Royce, in 1904. He was introduced to Charles Stewart Rolls on 4 May that year. The pair entered into a partnership in which Royce would manufacture cars to be sold exclusively by Rolls, and the cars would be called Rolls-Royce.
- RSA Security – formed from the first letters of the family names of its founders Ronald Rivest, Adi Shamir and Len Adleman.
Read more about this topic: List Of Company Name Etymologies