A spokesman says she was standing outside her unit´s base when a truck struck and killed her.
Spokesman Vincenzo Pugliese said the driver jumped out of the truck and fled the scene on foot after hitting the soldier. The incident is under investigation.
Neupane had been in Haiti since October 2010.
The incident occurred Tuesday near the central plateau town of Mirebalais. There are about 1,000 Nepalese peacekeepers in Haiti.
Haiti quake death toll rises to 1,419, injured now at 6,000