Party members will vote for four days from Sept. 24 to 27.
Members will cast ballots via a phone and Internet voting system.
The current leader, Adrian Dix, announced last September he would step down and the party appointed a committee to determine why it lost last year's provincial election.
Dix failed to unseat Premier Christy Clark's Liberals despite going into the election with a 20-point lead in public opinion polls.
Instead the New Democrats ended up with one less seat in the provincial legislature.
The deadline to join the party — and get to vote — is June 26.
Also on HuffPost