The veteran New Democrat says he made the decision after consulting with his family.
Stoffer says he appreciates the encouragement and support he's received.
The MP for Sackville-Eastern Shore was elected to the House of Commons in 1997 and is the Opposition critic for Veterans Affairs.
Former Nova Scotia premier Darrell Dexter announced his resignation as NDP leader last weekend after losing the provincial election last month.
Legislature member Maureen MacDonald is scheduled to be nominated as acting leader at an NDP provincial council meeting Saturday in Halifax.