The collision between the bus and a seven-year-old boy happened on Moston Lane East at around 6.20pm.
The boy sustained serious injuries and is being treated in hospital.
His injuries are thought to be “life-changing” but not “life-threatening”.
Greater Manchester Police (GMP) says there were no injuries reported to have been suffered by any passengers on the bus.
No arrests have been made.
The force has urged any witnesses who have not already spoken with them to come forward.
Anyone who believes they may have information or dashcam or CCTV footage of the incident, is being urged to contact GMP’s serious collision investigation unit on 0161 856 4741 or 101, quoting log 2,486 of October 12.
