A man in his 50s has been arrested in connection with the collision - he's being held at Kildare Garda Station under Section 4 of the Criminal Justice Act.
It happened at around 8pm on Thomas Street in Newbridge last night where a woman in her 40s was found with serious injuries.
She was taken to Naas General Hospital where she was pronounced a short time later.
Gardaí say the results of a post-mortem will determine the course of the investigation.
Anyone with information to the incident or has dashcam footage are being asked to contact Newbridge Garda Station.
Pride Of A County - Comeback Kings Wicklow Overcome 12-Point Mountain To End Wait For National Glory
No Changes To Starting Team As Wicklow Football Yearns For Historic Croker Triumph
Wicklow Braced Once More As Coillte Signal Orange Fire Warning
Wicklow Boss Targets Tailteann Cup Glory As Down Challenge Looms At Croke Park
Wicklow TD Calls For Straw Incorporation Funding For Struggling Tillage farmers
