Carl Paul Gottfried von Linde (11 June 1842 – 16 November 1934) was a German scientist, engineer, and businessman. He discovered the refrigeration cycle and invented the first industrial-scale air separation and gas liquefaction processes, which led to the first reliable and efficient compressed-ammonia refrigerator in 1876.

Linde was the founder of the company now known as Linde plc but formerly known (variously) as the Linde division of Union Carbide, Linde, Linde Air Products, Praxair, and others. This company is the world's largest producer of industrial gases and ushered in the creation of the global supply chain for industrial gases.

Linde was a member of scientific and engineering associations, including being on the board of trustees of the Physikalisch-Technische Reichsanstalt and the Bavarian Academy of Sciences and Humanities. He was knighted in 1897 as Ritter von Linde.

Born in Berndorf [de], Bavaria as the son of a German-born minister and a Swedish mother, he was expected to follow in his father's footsteps but took another direction entirely. Von Linde's family moved to Munich in 1854, and eight years later he started a course in engineering at the Swiss Federal Institute of Technology in Zurich, Switzerland, where his teachers included Rudolf Clausius, Gustav Zeuner and Franz Reuleaux.

In 1864, he was expelled before graduating for participating in a student protest, but Reuleaux found him a position as an apprentice at the Kottern cotton-spinning plant in Kempten. Linde stayed only a short time before moving first to Borsig in Berlin and then to the new Krauss locomotive factory in Munich, where he worked as head of the technical department. Von Linde married Helene Grimm in September 1866; their marriage lasted 53 years and they had six children.

In 1868 Linde learned of a new university opening in Munich (the Technische Hochschule) and immediately applied for a job as a lecturer; he was accepted—at the age of 26—for the position. He became a full professor of mechanical engineering in 1872, and set up an engineering lab where students such as Rudolf Diesel studied.

In 1870 and 1871, Linde published articles in the Bavarian Industry and Trade Journal describing his research findings in the area of refrigeration. Linde's first refrigeration plants were commercially successful, and development began to take up increasing amounts of his time. In 1879, he gave up his professorship and founded the Gesellschaft für Lindes Eismaschinen Aktiengesellschaft ("Linde's Ice Machine Company"), now Linde plc, in Wiesbaden, Germany. After a slow start in a difficult German economy, business picked up quickly in the 1880s. The efficient new refrigeration technology offered big benefits to the breweries, and by 1890 Linde had sold 747 machines. In addition to the breweries, other uses for the new technology were found in slaughterhouses and cold storage facilities all over Europe.

In 1888, Linde moved back to Munich where he took up his professorship once more but was soon back at work developing new refrigeration cycles. In 1892, an order from the Guinness brewery in Dublin for a carbon dioxide liquefaction plant drove Linde's research into the area of low-temperature refrigeration, and in 1894 he started work on a process for the liquefaction of air. In 1895, Linde first achieved success, and filed for patent protection of his process (not approved in the US until 1903). In 1901, Linde began work on a technique to obtain pure oxygen and nitrogen based on the fractional distillation of liquefied air. By 1910, coworkers including Carl's son Friedrich had developed the Linde double-column process, variants of which are still in common use today.