The victims were sitting in their car at a gas pump at about 9:35 p.m. when a blue Nissan Maxima pulled up and an unspecified number of suspects fired multiple shots, Memphis Police said on Twitter.
Two girls, ages 15 and 16, died. A 16-year-old girl and a 9-month-old boy were injured and in non-critical condition, according to police.
The gas station is on Elvis Presley Boulevard, just down the road from Graceland.
The suspect vehicle believed to be involved in the shooting has been recovered, but no arrests have been made, Memphis police said.
The motive is unknown and the investigation is ongoing, according to police.
Police are asking anyone with tips related to the shooting to call 901-528-CASH.