It happened on the Lissue Road, in the countryside on the edge of an industrial estate just to the west of the city.
The metal bridge supports a railway line, and has a clearance of 12ft 9ins (3.8m).
Images show the lorry trailer (covered in black canvas with no identifying branding) having crumpled and partially toppled over from the cab’s impact with the bridge.
Shortly after 9am, the PSNI said: “Road users are advised that the Lissue Road in Lisburn is currently blocked after a collision between a lorry and a railway bridge.
"Please avoid the area and seek alternative routes for your journeys."
They said the road had fully reopened by 12.15pm.
There were no injuries reported.
