Raymond Gray claims that the city was negligent by not implementing adequate safety measures.
In February, Gray was shot in the head at the former Rosewood Center in Owings Mills when instructor William Kern fired his live service weapon in an attempt to scare Gray away from a window.
Gray lost an eye in the accident and is undergoing rehab in the state of Pennsylvania.
Kern, meanwhile, has been charged criminally in the incident.
The multimillion-dollar lawsuit names as defendants the officers involved in the incident, the Baltimore Police Department and Baltimore city.
The suit was filed in Baltimore City Circuit Court on Friday.