Dozens of staff at bus operator McGill's are set to stage a series of strikes over a pay dispute.
The move comes after 85% of about 50 Unite union members, including drivers, shunters and labourers, voted to take industrial action.
Unite said depots at Inchinnan and Johnstone in Renfrewshire would be affected by three 24-hour strikes, starting on 26 November.
The other scheduled dates for action are 2 December and 9 December.
A continuous overtime ban will also be in place.
The union maintains that former Arriva Scotland West staff, who were transferred to McGill's after it took over its rival in 2011, have been lagging behind on pay.
Unite regional industrial officer Kenny Jordan said the former Arriva workers were being paid between 8% and 14% less than their co-workers.
He added: "Unite's members who previously worked for Arriva have been extremely patient and accepted that McGill's rates had to catch up.
"However, this position has been used as a cover by management to suppress the wages of around 50 of our members for eight years, which is not acceptable.
"The strong mandate we have received for industrial action is a reflection of the anger and injustice felt by the workers resulting in a series of days of action beginning from 26 November."
A spokesman for Greenock-based McGill's said: "McGill's has repeatedly and consistently offered pay parity for the ex-Arriva staff since they came on board in March 2012.
"This offer still stands and we would hope that this group of employees take up this offer to increase their take-home pay.
"There is enough resilience within McGill's to ensure that the strikes do not affect any bus services."