Valjoux SA was founded in 1901 by the brothers John and Charles Reymond in Les Bioux and until 1929 operated under the name "Reymond Frères SA". The company specialized in chronograph movements. In 1910 it moved to a factory building maintained by the municipality of Les Bioux.
The company's famous column wheel chronograph movement, Calibre 22, debuted in 1914 and lasted in production for sixty years. But it was larger than desirable for wrist watch use. The military, involved in the First World War, required reliable bracelet chronographs. Thereafter the 13-ligne chronograph Calibre 23 and 72 (diameter 29.33 mm, height 5.85 mm) was developed, which in 1916 came to the production stage and soon ticked in the wristwatches of very different manufacturers (for instance Audemars Piguet, Patek Philippe, Rolex, and Vacheron Constantin). The production lasted nearly sixty years, and until 1974 about 125,000 ebauche movements of this type were made.
Reymond Frères had used the brand "Valjoux" (short for Vallée de Joux) and cursive R (for Reymond) mark as early as 1920. By this time the company was specializing in chronographs, rattrapantes, and shaped movements. By 1923, Reymond was producing complete finished movements in addition to ebauches.
The generational change took place with the name change in 1929: The Reymond's sons Marius and Arnold took over the company, which was called "Valjoux SA" from then on. In the 1930 years the transition from pocket watch to wristwatch movements was performed. In 1944 the incorporation into the Ebauches SA followed, and the primary focus on chronograph movements was retained.
The company has now been entirely absorbed by the Swatch Group, the world's largest watch group. This also expresses in the name of the current calibers, adopted by Valjoux, such as the Valjoux 7750, now called ETA 7750; and similarly for the other chronograph calibers.