William Leymergie (born 4 February 1947 in Libourne) is a French journalist television producer and host, best known for the French breakfast television news show Télématin, broadcast on public broadcaster France 2 and TV5 in Canada. After completing an arts degree at University of Paris X: Nanterre, Leymergie began his career at the External Affairs and Cooperation department (now Radio France Internationale) of the Office de Radiodiffusion Télévision Française (ORTF) in 1970.

In 1972, he joined the children's programming department as well as the France Inter radio station. In 1974, he became a journalist at the TF1 television network. After a period at the National Audiovisual Institute (INA), Leymergie worked as a journalist in the children's programming department of Antenne 2 from 1978 to 1984, where he produced programmes such as Disney Dimanche in 1979 and Récré A2 in 1980.