"Sister" is the debut single by Australian pop music duo Sister2Sister, released on 4 October 1999.

It debuted on the ARIA Singles Chart at number 14, then after several weeks climbed inside the top 10; it peaked at number three on 12 December 1999.

[2] It spent a total of 20 weeks inside the top 50.

[2] In New Zealand, the single debuted on the RIANZ Singles Chart at number 14 and fell out quickly, spending eight weeks in the top 50.

[3] On the UK Singles Chart, "Sister" debuted at number 18, before falling 17 places the next week.