First Minister Arlene Foster told the Stormont Assembly the measure was being introduced to attempt to slow the spread of coronavirus.
The number of cases of Covid-19 has been rising in recent weeks, with 1,513 positive tests reported in the last seven days.
Mrs Foster described the increase in cases as “of serious concern to the North's Executive”, and said if not stopped, it will “inevitably lead to an increase in hospital admissions and deaths”.
The new curfew will apply from midnight on Wednesday to pubs, bars, restaurants and cafes as well as hotel and guesthouse bars.
“Building on the measures already in place, the Executive agreed last Thursday that a closing time of 11pm should be applied to the hospitality sector,” she said.
Pubs and eateries are being asked to call last orders at 10.30pm before closing at 11pm.
Mrs Foster added: “In practise, this brings the normal closing times forward by half an hour and there will be no late licensing.
There can be no exceptions to this, so weddings and other important social events will also be required to comply
“The intention behind the earlier closing time is that socialising later in the evening is considered to increase the risk of virus spreading because people adhere to the rules less strictly after consuming alcohol and in venues where they are used to mixing freely.
“There can be no exceptions to this, so weddings and other important social events will also be required to comply.”
The First Minister said the arrangements will be subject to enforcement.
It is a later closing time than the rest of the UK, where a 10pm curfew has been introduced, but earlier than the 11.30pm curfew in the Republic of Ireland.
Hospitality Ulster chief executive Colin Neill expressed concern at the sector losing hours.
“We respect that health has to come first, but this curfew and other restrictions must be kept under continuous review,” he said.
“The sector is going to lose hours, it’s losing staff and it has lost live music and needs to be given a fighting chance.
“A curfew is not ideal, but we in the hospitality sector will do all we can to make this work, which hopefully will be only a temporary measure.”
Executive ministers discussed the measure at a meeting last week.
Then, Mrs Foster said while there was a “strong unity of purpose on the way forward”, the Executive wanted to finalise more details.
Deputy First Minister Michelle O’Neill said it was about “dotting the Is and crossing the Ts”.
While most measures aimed at stemming the spread of coronavirus have been made in press conferences, the curfew decision was delivered in the Assembly following complaints from MLAs that they had not had the chance to ask questions.
Bars which do not serve food opened their doors again on Wednesday for the first time in six months.
In Northern Ireland, off-licences and supermarkets can sell alcohol until 11pm most days.
