Celestion is a British designer and exporter of professional loudspeakers.

What became Celestion was started in Hampton Wick (suburban London) in 1924. Cyril French and his three brothers had taken over a plating works and established the Electrical Manufacturing and Plating Company. They were listed as "electrical instrument manufacturers". Eric Mackintosh approached Cyril French for assistance with improving a new loudspeaker he had already filed a patent for (British Patent No. 230,552 on 15 December 1923, issued 16 March 1925). The BBC had started their programme in November 1922 and was building up new senders, public interest in radio broadcasting grew rapidly. But listeners still needed to connect either earphones or gramophone horns to the first radio receivers. Installing a loudspeaker sensitive enough in decorative cabinets quickly made these sought-after pieces of furniture in the roaring twenties. French and Mackintosh perfected the design, the modified French/Mackintosh model used a clamped edge, its conical paper diaphragm was strengthened with strips of Chinese bamboo (British Patent No. 245,704, filed 24 October 1925, issued 14 January 1926). Cyril French became the driving force of the endeavour to start manufacturing it in his company.

The first housed loudspeaker, Celestion, was launched in early 1925. Customers had a choice of oak, walnut or mahogany for the enclosure. One of French's brothers, Ralph, devised the name of the new product. He was also in charge of the cabinet designs and advertising, the two other brothers continued the plating business. A complete range with the models A1, A2, A3, A4 and A5 was introduced soon, and a subsidiary in Paris was formed, Constable-Celestion, to export first speakers. In 1927 the Celestion Radio Company and Celestion Ltd. were formed, which grew and became highly successful quickly. The new models C10, C12, C14 and C24 were brought to market, especially the C10 and C12 were highly praised. For many years Celestion advertising would carry the phrase "The very Soul of Music". In 1929 Celestion Ltd. moved across the Thames to Kingston upon Thames, now listed as "Gramophone Works".

In 1931 the C range of loadspeakers were supplemented by the new models D10, D12 and D50. Technological improvements meant Celestion had to stay up to date. The first electrical disc-playing machines appeared on the market in the late 1920s. These electric "phonographs" (since the 1940s known as record players, or nowadays as turntables) became more widespread, later to be combined with a radio receiver. Also in the 1930s receivers became more sophisticated and smaller, loudspeakers now were being built into the receiver cabinet itself, thus a separate unit was not necessary anymore. Many ingenious ideas were incorporated in new designs in order to raise the quality of sound reproduction, such as the Celestion Reetone and Reetone Dual matched speaker units. The former incorporated two equal-sized speakers with a transformer, the matched units were staggered. This eliminated the tendency to "boom" greatly, because the bass could be better suppressed. The latter had large and small speakers built in and a transformer. The two units were so coupled that the treble was accepted by the treble unit and the bass by the bass unit, being essentially a two-way, crossover-less splitting system. In 1932 Celestion brought the Ppm Permanent Magnet Moving Coil Speaker to market.

The business was hit hard by the Great Depression, like so many. Furthermore, in 1934 the British Rola Company, a dependance of the U.S. Rola Company of Cleveland, Ohio, opened in London. Rola being another loudspeaker manufacturer with similar products, the two companies began competing for home and export markets. In 1935 Cyril French resigned from the board of Celestion Ltd, Eric Mackintosh also left in the early 1930s.

With the 1940s wartime restrictions forced Celestion and the British Rola to produce loudspeakers to the same specification, the utility "W" type. Micro Precision Products, later a camera maker, was formed as a subsidiary during the war. British Rola bought Celestion in 1947 and moved production to Thames Ditton a year later. The name of the company now changed to Rola Celestion, with its products sold under the brand name Celestion. The company continued making radio, "high fidelity", and television speakers in the postwar years. In 1949, Rola Celestion was bought by Truvox, a public address system manufacturer.

In 1968 Celestion started production in Ipswich, Suffolk, moving all manufacturing there by 1975. The firm merged with a clothing company in 1970, and the result was now named Celestion Industries, which in turn became Celestion International Ltd. in 1979.

In 1992 the loudspeaker part of the business (Celestion International) was sold to Kinergetics Holdings (UK) Ltd., which also bought the company KEF.