Editing List of inventors (section)

===J===
* [[Moritz von Jacobi]] (1801–1874), Germany/Russia – [[electrotyping]], [[electric boat]]
* [[Rudolf Jaenisch]] (born 1942), Germany/U.S. – first [[Genetically modified mouse]]
* [[Alcinous Burton Jamison]] (1851–1938), American physician, inventor of medical devices
* [[Jang Yeong-sil]] (c. 1390–after 1442), South Korea (Joseon dynasty) – [[Borugak Jagyeongnu|Jagyeokru]] (Water clock) and [[Cheugugi]] (rain gauge)
* [[Karl Guthe Jansky]] (1905–1950), U.S. – [[radio telescope]]
* [[Karl Jatho]] (1873–1933), Germany – [[aeroplane]]
* [[Ali Javan]] (1926–2016), together with [[William R. Bennett Jr.]] (1930–2008), Iran/U.S. – [[Gas laser]] (Helium-Neon)
* [[Al-Jazari]] (1136–1206), [[Iraq]] – [[elephant clock]], [[humanoid robot]]s
* [[Ibn Al-Jazzar]] (Algizar) (895–979), [[Tunisia]] – [[sexual dysfunction]] and [[erectile dysfunction]] treatment drugs
* [[Ányos Jedlik]] (1800–1898), Hungary – [[Dynamo#Jedlik's dynamo|Jedlik dynamo]]
* [[Alec Jeffreys|Alec John Jeffreys]] (born 1950), UK – [[DNA profiling]] (forensics)
* [[Charles Francis Jenkins]] (1867–1934), U.S. – television and [[movie projector]] (Phantoscope)
* [[Thomas L. Jennings]] (1791–1859), U.S. – novel method of [[dry cleaning]]
* [[Jeong Yak-yong]] (1762–1836), South Korea (Joseon dynasty) – Geojunggi (crane)
* [[Steve Jobs]] (1955–2011), U.S. – Apple [[Macintosh]] computer, [[iPod]], [[iPhone]], [[iPad]] and other devices, software operating systems and applications.
* [[Amos E. Joel Jr.|Amos Edward Joel Jr.]] (1918–2008) U.S. – electrical engineer, known for several contributions and over seventy patents related to telecommunications switching systems
* [[Carl Edvard Johansson]] (1864–1943), Sweden – [[Gauge blocks]]
* [[Johan Petter Johansson]] (1853–1943), Sweden – [[Pipe wrench]] and [[adjustable spanner]]
* [[Reynold B. Johnson]] (1906–1998), U.S. – [[Hard disk drive]]
* [[Philipp von Jolly]] (1809–1884), Germany – [[Jolly balance]]
* [[Scott A. Jones]] (born 1960), U.S. – created one of the most successful versions of [[voicemail]] as well as [[ChaCha Search]], a human-assisted [[internet]] [[Web search engine|search engine]]
* [[Tom Parry Jones]] (1935–2013), UK – first electronic [[Breathalyzer]]
* [[Assen Jordanoff]] (1896–1967), Bulgaria – [[airbag]]
* [[Anatol Josepho]] (1894–1980), patented the first coin-operated [[photo booth]] called the "Photomaton" in 1925
* [[Marjorie Joyner]] (1896–1994), U.S. – [[Permanent wave]] machine
* [[Whitcomb Judson]] (1836–1909), U.S. – [[zipper]]
* [[Percy Lavon Julian]] (1899–1975), U.S. – chemical synthesis of medicinal drugs from plants
* [[Ma Jun (mechanical engineer)|Ma Jun]] (''fl.'' 220–265), China – [[south-pointing chariot]] (see [[differential gear]]), mechanical [[puppet]] [[theater]], [[chain pump]]s, improved [[silk]] [[loom]]s