The 17-year-old, who can't be named under the Youth Criminal Justice Act, faces four counts of first degree murder, seven counts of attempted murder and unauthorized possession of a firearm.
RCMP say nine people were shot at the La Loche Community school.
A teacher and a teacher's aide died in the tiny community and seven others were wounded.
The outside of La Loche Community School is shown on Jan. 22, 2016. (Joshua Mercredi/The Canadian Press)
The bodies of two teenaged brothers were found at a nearby house.
The suspect will appear in provincial court in Meadow Lake, about 270 kilometres south of La Loche.
Saskatchewan's two most senior politicians visited La Loche on Sunday to meet with local leaders and offer support.
Premier Brad Wall and federal Public Safety Minister Ralph Goodale say the discussion covered a number of topics, including mental health services, health-care funding and when the school should reopen.
The dead have been identified as teacher Adam Wood, 35, teaching aide Marie Janvier, 21, Drayden Fontaine, 13, and Dayne Fontaine, 17.
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