Jaak is a version of the name Jacob in Estonian language.
People named Jaak include:
Jaak Aab (born 1960), Estonian politicianJaak Aaviksoo (born 1954), Estonian politician and physicistsJaak De Boever (born 1937), Belgian racing cyclistJaak Boon (born 1948), Belgian television writer, director and producerJaak Gabriëls (born 1943), Belgian politicianJaak Huimerind (born 1957), Estonian architectJaak Joala (1950–2014), Estonian singerJaak Jõerüüt (born 1947), Estonian writer and politicianJaak Juske (born 1976), Estonian politicianJaak-Nicolaas Lemmens (1823–1881), Belgian organist and composerJaak Lipso (born 1940), Estonian basketball playerJaak Madison (born 1991), Estonian politicianJaak Mae (born 1972), Estonian cross-country skierJaak Panksepp (born 1943), Estonian-American psychologist, psychobiologist and neuroscientistJaak Põldma (born 1988), Estonian tennis playerJaak Salumets (born 1949), Estonian basketball player and coachJaak Tamm (1950–1999), Estonian politician and businessmanJaak Urmet, better known as Wimberg (born 1979), Estonian poet and writerJaak Uudmäe (born 1954), Estonian triple jumperJaak van Velthoven, Belgian motocross riderJaak van Wijck (1870–1946), Dutch painter