The 81-year-old was struck by the HGV on Westgate in Heckmondwike on Wednesday afternoon.
Officers were called to the scene at 3.45pm followng reports.
The man, who is local to the area, was rushed to Leeds General Infirmary with serious head injuries but was sadly pronounced dead.
West Yorkshire Police are appealing to any potential witnesses to the collision, or anyone who may have dash cam footage of what happened, to come forward.
Anyone with information should contact police on 101 quoting log reference 1007 of 08/01.