The National Accountability Bureau (NAB) court handed down the verdict after a series of delays.
His daughter and son-in-law were also convicted.
Sharif, who is currently in London and was sentenced in absentia, says the charges are politically motivated and has vowed to return to Pakistan.
“I will go back. I will continue my struggle even in the jail,” he told reporters.
Sharif gave no date for his return. His wife, Kulsoom Nawaz, is receiving treatment in London for cancer.
Sharif’s lawyer Abdul Rashid Sheikh, speaking in Pakistan, confirmed that they would appeal against the conviction.
Judge Mohammad Bashir ordered Sharif to serve 10 years for owning assets beyond income and one year for not co-operating with the NAB. The sentences are to be served concurrently.
Daughter Maryam Nawaz Sharif, also in London, received seven years for abetting a crime and one year for not co-operating – again to run concurrently – while son-in-law Safdar Awan was given a one-year sentence for not co-operating.
Sharif and Maryam also received fines of £8m ($10.6m) and £2m respectively.
The case, known as the Avenfield Reference, relates to a number of properties in the UK capital.
The Panama Papers leak in 2015 revealed several of Sharif’s children had links to offshore companies, which were allegedly used to channel funds and buy foreign assets – including luxury flats in Avenfield House, on London’s Park Lane.
His family, however, insist they legitimately acquired the four properties.
As part of the ruling, the court ordered they be confiscated for the federal government. (BBC)