Around 1:30 p.m., police were called to the intersection of Thames and Charles streets.
Members of Oxford OPP, along with Ingersoll Fire Services and Oxford County Emergency Medical Services attended the scene.
Initial investigation revealed that a pedestrian pushing a stroller was crossing the road when a transport truck hit the pedestrian.
The pedestrian was taken to hospital with life-threatening injuries and was later pronounced dead. Their identity has not yet been released.
The infant in the stroller was taken to hospital with minor injuries, and the driver of the truck was not injured, OPP say.
The intersection has been closed for investigations.
Anyone with further information is asked to contact the Oxford County OPP at 1-888-310-1122.