The 15-year-old boy from Worongary was riding an electric dirt bike along a road in Broadbeach about 3am when he lost control and fell off, police said.
Investigators are probing if he was going too fast.
Legal e-bikes can be ridden on paths unless otherwise signed, as long as riders obey bicycle rules such as wearing a helmet.
They must have a maximum continuous power output of 250 watts and be pedal-powered with motor assistance up to 25km/h.
There are no age limits for riding e-bikes in Queensland.
Bikes with motors over 250 watts are illegal, as are throttle-powered bikes without pedals, which are technically electric motorcycles and require registration, insurance and a licence and cannot be ridden on paths.