I assume you are asking about Barbie's sister Kelly. Kelly is named Shelly in Europe. Since Barbie's surname is Roberts, so is Kelly's/Shelly's.
It's also possible that Shelly's given name is Michelle.
As of 2011, the Kelly/Shelly doll was rechristened Chelsea. Mattel said that the doll's first name was still Kelly but she was now going by her middle name of Chelsea. So, as of April 2011, her name is Kelly Chelsea Roberts.
The same doll was named Kelly in North America and Shelly in Europe.
Shelly-Ann Fraser (full name: Shelly-Ann Fraser-Pryce) is a Jamaican from Jamaica. See the related link below.
Shelly Pinder's birth name is Shelly Denning.
Shelly Howard's birth name is Shelly Fletcher.
Allison Mack
Shelly Lipkin's birth name is Shelly Miles Lipkin.
Shelly Jennings's birth name is Shelly R. Karmann.
Shelly Martinez's birth name is Shelly Lenore Martinez.
Shelly Leigh's birth name is Leigh Shelly Burkhart.
shelly come from a Italian name meaning "very smart in the brain" and it is the best name because its my moms name shelly k. m.
Midge is a nickname for Margaret. The doll's full name is Margaret Hadley Sherwood.
Shelly Manne's birth name is Manne, Sheldon.