Emergency services said paramedics tried unsuccessfully to resuscitate the boy when they were called to the scene of the strike in Bloxwich, in the West Midlands of central England, at 7:50 a.m. (0650 GMT).
They did not release his name, but media reports identified him as Joseph Wharton.
In London, the ambulance service said four young women were injured by a lightning strike in Hyde Park and one of them had stopped breathing.
Paramedics rushed her to a nearby hospital but the ambulance service did not know whether she was resuscitated. It was not immediately clear how badly the others were hurt.
The storms in southern and central England were isolated but powerful.
While only traces of rain fell east of London, Heathrow Airport to the west received 17 millimeters (0.7 inches), most of it within about two hours, said weather forecaster Brendan Jones.
High Wycombe in Buckinghamshire, northwest of London, got 42 millimeters (1.7 inches) in an hour, Jones said.
The rain caused disruptions around the London Underground and some train lines and about 50 arriving and departing flights were either canceled or badly delayed at Heathrow.
