While many daytime restrictions were eased until June 1, residents have to stay home from 9 p.m. to 5 a.m. on weekdays, as well as the entire weekend, with exceptions such as walking to the closest market to buy groceries, dpa news agency.
The 17-day lockdown was imposed after new daily infections crossed an all-time high of more than 60,000 in April, while the pace of vaccinations slowed.
The Interior Ministry said shopping malls will be open on weekdays, while restaurants and cafes are limited to only take-away and delivery services.
Cinemas, sports facilities and bars remain shuttered and schools will continue with their remote learning schedules.
Inter-city travel is allowed, except during curfew hours.
Foreign tourists, however, face no restrictions.
President Recep Tayyip Erdogan had said the aim was to reduce new daily cases to below 5,000 and also revive the crucial tourism industry.
More than 10,500 new infections were reported in the last 24 hours in the country of 84 million.
The total number of cases has increased to 5,117,374 since last March, while the death toll is 44,760.
Nearly 26 million have received their first vaccine, but only 10.9 million are fully vaccinated with their mandated second jab.