A month before his 99th birthday, Niemeyer, famous for Modernist designs including the National Congress building in Brazil's capital Brasilia, has married 60-year-old Vera Lucia Gabreira.
In a short statement, Niemeyer said: 'Vera and I got married [on Nov 16] in my residence, in a simple ceremony witnessed by the civil authorities who performed the wedding and a small group of friends.'
Niemeyer, whose career spans seven decades, is responsible for 175 projects worldwide, including the 2003 Serpentine pavilion in Hyde Park, London and the layout for the UN's New York headquarters.
Arguably his best known creation is the National Congress building, resembling two huge white bowls - one inverted - with twin towers rising in between.
Following the 1964 Brazilian military coup, Niemeyer - a confirmed communist - fled to France, where he designed the distinctive French Communist Party HQ in Paris. He returned to Brazil after the military dictatorship turned into democracy in 1985.
Niemeyer was awarded the RIBA Gold Medal in 1998, but a fear of flying prevented him leaving Brazil to collect the prize personally.
Gabreira is Niemeyer's second wife - his first wife of 76 years, Anita Baldor, died in 2004.
The newly married couple have known each other for 30 years, according to the International Herald Tribune.
Niemeyer has one daughter, five grandchildren, 13 great grandchildren and five great-great grandchildren.