The incident happened in Carmuirs Avenue between 5pm an 5.30pm on Friday, May 27.
The victim was walking near to the junction with Mariner Road when a man walked past her, before turning back and assaulting her.
He is described as white, in his late 30s, around 5ft 8in tall with a medium build and short fair hair.
He was wearing a dark blue zip-up cardigan with a red t-shirt underneath and dark jeans.
DC Grant Stronach, of Falkirk CID, said: “This attack was completely unprovoked and it’s possible that someone witnessed this from a nearby house.
“If anyone recognises the description of this man and remembers seeing him around the time of the incident, please call us.”
Anyone with information can contact Police Scotland on 101 or Crimestoppers on 0800 555 111.