His announcement comes after he promised at the first lockdown extension at the end of October that officials would "re-evaluate" the situation after two weeks.
"We're at those two weeks now," Legault said.
"Unfortunately the indicators show us that we need to be even more cautious."
Unfortunately, we have not succeeded in reducing the number of new cases each day.
"I'm announcing that for the next two weeks, the measures that were announced will remain in place."
The current round of closures in Quebec's red zones took effect on October 1 for what was supposed to be a period of four weeks.
But as the second COVID-19 wave ramped up, the government extended the lockdown to November 23, pending that two-week review.
Restaurants, bars and gyms are among the businesses that have had to close their doors.
Legault has faced mounting criticism, however.
A coalition of 200 gyms initially promised to defy the government and open on October 29 before giving in to threats of fines for owners and customers, alike.
The Direction Régionale de Santé Publique (DRSP) de Montreal has also asked the provincial government to allow gyms to reopen under certain conditions.