Police say three masked men, two armed with handguns, forced their way into the property in Glenfearna Gardens in the Lagmore estate at around 10.45 pm on Friday night.
They threatened the women, aged 81, 49, and 25, and tied up the 49-year-old during the robbery.
The gang left in a small silver vehicle with a substantial sum of cash.
One of the women, Saoirse Joyce, said it was a traumatising experience.
“They barged into my room – two masked men that I could see,” she said.
“I just jumped up to the window and pushed the window open and shouted out help, but one of them trailed me down by the hair onto the ground and said to the other one ‘hold her there’.
“He pointed a gun to my head and I couldn’t move and all I kept saying was ‘my granny, my granny’,”.
Det Const Fiona Mills said: “This was a despicable act perpetrated against three generations of the one family.
“All of these women have been left understandably extremely shaken and upset by the ordeal.”
DC Mills has appealed for anyone with information to contact her on the 101 non emergency number.
Alternatively, information can be passed anonymously through Crimestoppers on freephone 0800 555 111.