The Ministry of Public Health urged the country to adhere to the Covid-19 measure, which was introduced on July 7.
The Council's announcement reverses a decision on May 18 to scrap the mask rule in indoor public spaces, except healthcare centres and on public transport.
The rule will be introduced across public spaces including healthcare centres, work sites, public transport, mosques, gyms, shopping centres, shops and cinemas.
On Monday, Qatar registered 599 new cases of Covid-19, with 5,045 active cases overall. It has recorded a daily average of 637 recoveries over the past seven days.
The ministry emphasised the need for people to be vaccinated against the infection and said more than 1.7 million people in Qatar had received a booster dose.
The ministry said a fourth shot was now available for people aged 50 and over, as well as patients who suffered from chronic diseases that increased the risk of severe complications from Covid-19.
Last October, Qatar’s Cabinet eased Covid-19 restrictions at a time when the daily infection rate was dropping.
People no longer needed to wear a mask during outdoor activities, except at public events, markets and exhibitions.