Dyalog APL (1 character), 1 byte
⍋ Dyalog APL has a built in operator function (thank you Zacharý for clearing this up) to do this.
Example
⍋11 2 4 15 2 3 1 4 {⍵[⍋⍵]}11 4 2 15 2 4 11 15 Here I'm indexing into the list by the sorted indices to return the list in ascending order.