Denon is a Japanese electronics company founded in 1910 by Frederick Whitney Horn, an American entrepreneur.
The name came about as an abbreviation of the names of the Denki and Onkyo companies (the latter not to be confused with the Onkyo company), which were integrated with other companies in 1939.

The company produced the first phonograph cylinders in Japan, as well as the phonographs used to play them. Decades later, the company was involved in the early stages of the development of digital audio technology, while specialising in the manufacture of hi-fi equipment for both professional and consumer applications. Denon built Japan's first professional disc recording machine which was used to record Emperor Hirohito's speech, the historic radio address on 15 August 1945 that ended World War II with the surrender of Japan. For many decades, Denon would be a brand of Nippon-Columbia, which also included its own record label.

The company was originally established in 1910 as part of Nippon Chikuonki Shokai (Japan Recorders Corporation), a manufacturer of single-sided records and gramophones.1 Initially, the company was called Nippon Denki Onkyō Kabushikigaisha (日本電氣音響株式會社 Japan Electric Sound Company), which was shortened to Denon. It was active in the production of sound systems and electrical appliances, and subsequently merged with other related companies, which adopted the Denon name.

A series of mergers and business linkages followed over the next few decades, as it first merged with Japan-US Recorders Manufacturing in 1912, and then in 1928 the "Columbia" brand name was introduced when the company became Japan Columbia Recorders. Another name change occurred in 1946, when the company was renamed Nippon Columbia.

The Denon brand was first established in 1947 when Nippon Columbia merged with Denki Onkyo Japan.

In 2001, Denon was spun off as a separate company, with 98% owned by Ripplewood Holdings and the remaining 2% owned by Hitachi.

In 2002, the company merged with Marantz to form D&M Holdings.

On 1 March 2017, Sound United LLC completed the acquisition of D+M Holdings.

Today, the company specialises in professional and consumer audio and home theatre equipment, including audio and video receivers, DJ controllers, Blu-ray players, tuners, headphones and wireless music systems.
Denon is also known for its high-end receivers and turntable moving coil cartridges.
Two models of the M Series, the Denon M31 and M30, were the most successful radio hi-fi systems in the mid-2000s.
Since their launch in the hi-fi DAB microphone market, they have received several awards in Europe.