Johannes Gijsbertus Bastiaans (31 October 1812, Wilp - 16 February 1875, Haarlem) was a Dutch organist, composer and music theorist. Bastiaans was educated in organ playing from the age of ten in Deventer. He studied to become a watchmaker and settled in Rotterdam. There he meet C.F. Hommert, who introduced him to the works of Johann Sebastian Bach.