Mr Ratcliffe, who lives in Hampstead, north London, said his wife was "heartbroken" on Friday and accused the Iranian authorities of handing her “a punishment without a crime.”
"Five years is ridiculous…we will appeal,” she told him over the phone, “but I don't know how long it will take, how long it will last.
"I told her she has nothing to apologise for," Mr Ratcliffe said, "her head will always be high, she is much loved."
Mrs Zaghari-Ratcliffe was arrested in April at Tehran airport during a visit to see her family.
Her two-year old daughter, Gabriella, had her passport taken away following her mother’s arrest and is now living with her grandparents in Iran.
Iran’s Revolutionary Court has previously accused the charity worker of trying to overthrow the country’s clerical government. More...
“Iran’s Revolutionary Courts are notorious for handing down prison sentences after grossly unfair trials.
“From all the reports we’ve seen, Nazanin’s case has been a complete travesty of justice throughout, beginning with her protracted secret detention, then the unsupported accusations from officials and culminating in this week’s out-of-the-blue sentence.
“We’re calling on the UK Government to make urgent representations on Nazanin’s case at the highest level."
The announcement comes just days after Britain and Iran announced that diplomatic ties had been restored despite the fact that four Britons are still being held in Iranian jails.
Among them is Kamal Foroughi, a 77-year-old grandfather who is in danger of going blind, and Roya Nobakht, 49, from Stockport.
In 2011, Britain was forced to close its embassy in Tehran after it was stormed and looted by a pro-regime mob.