The members of the main opposition Citizens Coalition for Change (CCC) were arrested along with leading lawmakers Job Sikhala and Godfrey Sithole on June 14. They each had to pay bail of 50,000 Zimbabwe dollars (US$78).
"We breathe a sigh of relief that 14 of our members were granted bail," party spokeswoman Fadzai Mahere told AFP.
"However we condemn the continued abuse by Zanu-PF (the ruling party) of state institutions including the police service, the prison service and the court system to silence political opponents," she said.
Sithole was released last week while his colleague, firebrand lawyer Sikhala remains detained at a maximum security prison on the outskirts of Harare. Sikhala has been arrested 67 times but never convicted during a political career spanning more than two decades.
Mahere said there has been "rising violence, persecution and arbitrary arrests of our members for absolutely no reason, all on flimsy charges."
The releases came just days after a mission from the Commonwealth arrived to assess if conditions were conducive to warrant Zimbabwe's readmission into the group of mainly former British colonies.
Ex-strongman Robert Mugabe angrily pulled Zimbabwe out of the Commonwealth in 2003 after its membership was suspended over violent and graft-ridden elections the previous year.
Zimbabwe will hold general elections next year.