They include 59-year-old flight attendant Sandra Lee and her 25-year-old daughter Savanna Lee, a real estate agent, both from Minneola in the US state of Florida.
Their cousin Donna Brown, a 55-year-old nurse from Winter Gardens in Florida, also perished.
Three other relatives are hospitalised.
Reports are that about 12:15 a.m., the six were travelling in a Toyota Axio motor car towards Montego Bay, from Falmouth in Trelawny.
On reaching a stoplight on the Ironshore main road, the driver reportedly lost control of the vehicle and collided in another vehicle travelling in the opposite direction,.
Lee, her daughter and Brown, were flung from the car.
Savanna Lee and Donna Brown reportedly received severe head injuries, and died on the spot.
Sandra Lee was rushed to hospital but died while undergoing treatment.
The other three, including the driver of car, are reportedly in critical condition.
