The 2015 school holidays calendar has been officially released by the MOE. You can check all the dates by scrolling down, remembering to look at your correct table (whether Kumpulan A or Kumpulan B).
The dates below are from the MOE website, so are considered the official school holidays dates for 2015.
Kumpulan A Schools 2015 (Johor, Kedah, Kelantan, Terengganu)
[Kumpulan A 2015] Start date End date
Term 1 holidays 13 Mar 21 Mar
Mid-year holidays 29 May 13 Jun
Term 2 holidays 18 Sep 26 Sep
End-year holidays 20 Nov 2 Jan (2016)
Kumpulan B Schools 2015 (Kuala Lumpur, Labuan, Melaka, Negeri Sembilan, Pahang, Perlis, Penang, Perak, Putrajaya, Sabah, Sarawak, Selangor)
[Kumpulan B 2015] Start date End date
Term 1 holidays 14 Mar 22 Mar
Mid-year holidays 30 May 14 Jun
Term 2 holidays 19 Sep 27 Sep
End-year holidays 21 Nov 3 Jan (2016)