Suad al-Shammari had spent around 90 days at a women’s prison in the Red Sea city of Jeddah, her daughter Sarah al-Rimaly told AFP.
"She’s released now, thanks be to God," Rimaly said.
She added that her mother was released three days ago after signing a pledge "to reduce her activities".
She was arrested in late October for insulting Islam, activists said at the time.
Shammari had posted comments on Twitter about Islamic religious leaders.
Saudi Arabia’s new King Salman late on Thursday issued an amnesty for some prisoners, but Rimaly said her mother’s release was unconnected to this.
Rimaly added that she does not think the amnesty will cover Badawi, who is serving a 10-year jail sentence for insulting Islam.
He was also ordered to receive 1,000 lashes, a punishment which has drawn worldwide outrage and been dismissed as "cruel and inhuman" by UN human rights chief Zeid Ra’ad Al Hussein.
Badawi received the first 50 lashes of his sentence publicly in Jeddah on January 9.
Subsequent rounds of flogging were postponed for the following two weeks on medical grounds.
A session last Friday was also deferred, said his wife Ensaf Haidar.
