Rohey Hydara also expressed her condolences to the families of the victims and wished a speedy recovery to those who were injured.
In a statement released to the UK's Press Association via the Metropolitan Police on Tuesday, Hydara said: "I am saddened and shocked by what Khalid has done. I totally condemn his actions.
"I express my condolences to the families of the victims that have died, and wish a speedy recovery to all the injured. I would like to request privacy for our family, especially the children, at this difficult time."
Hydara spoke after Masood's mother, Janet Ajao
, said Monday in a statement that she was "deeply shocked, saddened and numbed" by the attack and had "shed many tears" for her son's victims.
Masood, 52, rammed a car into pedestrians on Westminster Bridge on Wednesday, killing three people and leaving dozens injured.
After crashing the vehicle he fatally stabbed an on-duty police officer at an entrance to Parliament. Another officer shot him dead.
London's Metropolitan Police say they don't believe Masood, who was born in the south-east of England and used multiple aliases, was directed by ISIS or al Qaeda.
He reportedly lived with his family
in Birmingham, central England, until December.
American tourist Kurt Cochran, 54, British citizen Aysha Frade, 44, and police constable Keith Palmer
, 48, died in the attack.
A fourth victim, 75-year-old Leslie Rhodes of south London, died Thursday night after his life support was withdrawn, police said.