The 19-year-old woman was critically injured with wounds to her neck and head during a drive-by shooting at Fitzy's Hotel in Loganholme, south of Brisbane, on Saturday night.
Multiple shots were fired at the venue about 8.15pm, when a boxing meet for Logan City Titles was taking place.
Police say they are looking for at least three people involved, including a masked shooter and a getaway driver.
Detective Inspector Ian Galpin said a Mitsubishi vehicle stopped near a number of people gathered outside the venue close to a drop-off zone.
"A number of shots were then fired from the front passenger window of that vehicle, striking four persons," he said.
Witnesses reported seeing two men inside the car wearing balaclavas and gloves, Det Insp Galpin added.
The car was later found set alight about 12km from the scene.
A second vehicle - a dual-cab utility - was captured on CCTV collecting the occupants of the abandoned car.
It was also found set alight later that evening. Both vehicles are being forensically examined.
Detectives say a level of pre-planning was involved in the attack, but they were struggling to establish a motive.
The teenage victim, who underwent emergency surgery on Saturday night, was not thought to be an intended target, Det Insp Galpin said.
Three men, aged 27, 37 and 38, are also recovering in hospital in serious but stable conditions.
All three had surgery after being shot in the abdomen.
Police said they are waiting for an opportunity to speak to the victims while detectives review CCTV footage.
A major police response was seen outside the venue on Saturday night and into the early hours of Sunday.
Bullet holes were visible on the outside of the building.
Logan City Titles said they were heartbroken and "praying for full recoveries" for those injured in the shooting.
"As a team, we are working through it and dealing with the emotions that come with this," the event organisers said in a statement.
Queensland Premier David Crisafulli described the attack as a "horrendous crime", adding his government had passed the strongest laws in the country to target drive-by shootings.
"It's just completely unacceptable that people on a night out at a pub, doing something as Queenslander as you can possibly find, can be caught and find themselves as collateral damage," he told reporters.
Logan mayor Jon Raven said the community has never seen anything like the shooting before.
"Everyone there will be processing trauma, especially the kids," he said.
"If you know someone who was (at) Fitzy's last night, please wrap your arms around them and make sure they know the community is thinking of them."
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