The shootings occurred around 3 p.m., shortly after classes ended for the day at Hope Academy of West Michigan. The victims were being treated at local hospitals.
The scene following the shootings was described by authorities as "chaotic." The school, which has students from preschool to 12th grade, was placed on lockdown.
A 17-year-old female student was struck in the leg, though details about the other student's injury weren't immediately clear. But they were able to get back to the school after being shot.
A 16-year-old boy, who isn't believed to be a student at the school, was shot in the side and found collapsed in the neighborhood.
Grand Rapids Police Capt. Eric Payne said it was unclear what prompted the shootings. Police were looking for three suspects.
"It did not happen on school property," Payne said. "We believe it was somewhere on Lafayette, near the school."
Superintendent Heidi Cate said in a statement that, "based on the reports of staff who witnessed the incident, we do not believe the suspects are Hope Academy students."