Niels Fabian Helge von Koch (Stockholm, January 25, 1870 – ibidem, March 11, 1924) was a Swedish mathematician who gave his name to the famous fractal known as the Koch snowflake, one of the earliest fractal curves to be described.

He was born into a family of Swedish nobility. His grandfather, Nils Samuel von Koch (1801 – 1881), was the Attorney - General of Sweden. His father, Richert Vogt von Koch (1838 – 1913) was a Lieutenant - Colonel in the Royal Horse Guards of Sweden. He was enrolled at the newly created Stockholm University College in 1887 (studying under Gösta Mittag - Leffler), and at Uppsala University in 1888, where he also received his bachelor's degree (filsofie kandidat) since non - governmental college in Stockholm had not yet received the rights to issue degrees. He received his Ph.D. in Uppsala in 1892. He was appointed professor of mathematics at the Royal Institute of Technology in Stockholm in 1905, succeeding Ivar Bendixson, and became professor of pure mathematics at Stockholm University College in 1911.

Von Koch wrote several papers on number theory. One of his results was a 1901 theorem proving that the Riemann hypothesis is equivalent to a stronger form of the prime number theorem.

He described the Koch curve in a 1904 paper entitled "On a continuous curve without tangents constructible from elementary geometry" (original French title: "Sur une courbe continue sans tangente, obtenue par une construction géométrique élémentaire").