The country’s state press service released images of the ceremony, which took place in the capital, Minsk.
Lukashenko was declared the landslide winner of the vote in August, but opposition figures have publicly accused him of rigging the poll, and have since disappeared from the country.
Tens of thousands of protesters have also taken to the streets in mass demonstrations across Belarus for weeks.
Lukashenko, who has been in power since 1994, assumed the office for his sixth consecutive term on Wednesday after taking an oath, state press service Belta reported.
“Assuming the office of the President of the Republic of Belarus, I solemnly swear to faithfully serve the people of the Republic of Belarus, respect and protect the rights and freedoms of man and citizen, observe and protect the Constitution of the Republic of Belarus, sacred and conscientiously fulfil the high duties entrusted to me,” the oath read.
The ceremony took place in the Palace of Independence and several hundred people were invited, according to the press service.
Belta said that senior officials, deputies of the House of Representatives, heads of state bodies, scientists, culture and sports figures were invited.
Over recent weeks, Lukashenko and the Belarusian state security apparatus has been forcibly removing from the country or detaining leading opposition figures.
Meanwhile, demonstrations have continued across the country, particularly at weekends. On Saturday, 430 people were detained in protests across the country, according to the Interior Ministry. Of those, 415 were in the capital Minsk. Some 385 people had been released as of Sunday morning, the Ministry said.