The three women are believed to have offered assistance to a 17-year-old girl who on the canal towpath near Tesco, at Weavers Wharf.
They helped the girl between 2.30am and 5am on Monday, May 31.
A spokesman for West Mercia Police said: "We are appealing to the three women who helped a 17-year-old girl on Monday, May 31, in Kidderminster.
"At a time between 2.30am and 5am, three woman offered assistance to a 17-year-old girl who was on the canal towpath near Tesco, Weavers Wharf, in Kidderminster.
"We believe the three people may be able to help with our investigation so would appreciate if they could get in contact or if anyone else saw the lone girl near this area at the time please contact DC Robinson from Kidderminster station on 01562 826057 reference 201i June 4."