Johnny Weltz (born March 20, 1962) is a Danish retired road bicycle racer. He rode most of his career for the Spanish ONCE team.
In 1985 he won silver at the world championship for amateurs. The high point of his career was his victory at stage 19 (a mountain stage) of the 1988 Tour de France, and was 54 overall. He also won a stage in Vuelta a España the same year. Later, he participated in the Tour de France 1990 (abandoned stage 14), 1991 (abandoned stage 18), and 1992 (overall 102).
After his active career, he worked in various capacities for the professional teams Motorola, US Postal, and CSC (back then called MemoryCard - Jack&Jones, and later CSC - World Online). Weltz is currently a directeur sportif with Team Slipstream.