Boeing shares tumbled by as much as 7 per cent after television footage showed the Dreamliner surrounded by foam used by firefighters at Heathrow.
Heathrow briefly closed both its runways to deal with the fire, which broke out while the aircraft was parked at a remote stand. There were no passengers aboard the plane.
Television footage showed an area on the fuselage in front of the tail that appeared to be scorched.
It was not clear if the fire was related to the batteries which were the cause of the previous fires on the Dreamliner.
"A Boeing 787 Dreamliner suffered an on board internal fire," a Heathrow spokeswoman said.
"The plane is now parked at a remote parking stand several hundred metres away from any passenger terminals."
Boeing said it was aware of the fire and that it had people on the ground working to understand the causes of it.
The US Federal Aviation Administration (FAA) said it was aware of the fire and was in contact with Boeing.
"This is terrible for the Dreamliner, any event involving fire and that airplane is going to be a PR disaster for Boeing," Christine Negroni, an aviation writer and safety specialist based in New York, said.
"Because of the battery issue, the public is even more sensitive to events that happen to the Dreamliner.
"Even if they are normal, benign teething problems, that subtlety is going to be lost on the public."
Another Boeing Dreamliner operated by Thomson Airways returned to the United Kingdom due to technical issues as a precaution, TUI Travel said.
Ethiopian Airlines said its aircraft had been parked at Heathrow for more than eight hours before smoke was detected.