The move comes as train conductors bring to a halt virtually all ScotRail Sunday trains outside Glasgow in a series of walkouts over the same issue which are due to continue until May 2.
In the latest ballot, ticket examiners voted by 238 to 44 to strike.
They work on electric trains in and around Glasgow, including on the line to Edinburgh via Bathgate.
Unlike conductors, who control doors on trains elsewhere, any action by ticket examiners is not expected to automatically lead to cancellations.
However, the Rail, Maritime and Transport union (RMT), which staged the ballots, said it could cause other problems.
Scotland organiser Mick Hogg said: “With no second person on the train [with the driver], Scotland’s trains would become a magnet for anti-social behaviour and assaults.
“There would be no revenue collected and our disabled passengers would become more vulnerable.”
RMT general secretary Mick Cash said: "Our ticket examiners have now joined our conductor members in this fight for equality with other ScotRail grades over enhanced payments and it’s now time for Abellio to get out of their bunker and do the right thing by their staff.
“The political leadership in Scotland can no longer sit on the fence and ignore these disputes in their back yard.
"It's time for serious talks, a serious approach to workplace fairness and justice and a serious solution to be reached."
ScotRail said it would await information about any action planned, which it said would be “reckless” with two and half weeks to go until mainland Scotland travel restrictions are expected to be scrapped.
Head of customer operations Phil Campbell said: “I’m disappointed the RMT’s ticket examiner members have voted for strike action when we are in the midst of the pandemic.
“When we are on the cusp of safely welcoming customers back onto Scotland’s Railway as lockdown restrictions ease, strike action over increased overtime payments is completely wrong for staff and customers.
“We will do everything we can to minimise the impact on customers, particularly those key workers who are reliant on our services, but services may have to be cancelled.
“ScotRail is currently facing the most significant crisis in its history.
"At a time when we need everyone to work together to rebuild and create a more sustainable railway for the future, the actions of the RMT bosses are reckless.”
The second of a planned series of six consecutive Sunday strikes by conductors on Easter Sunday halted nearly half of ScotRail’s 1,090 services, including all of those on lines outside the Glasgow area apart from the Bathgate route to Edinburgh.
All four ScotRail unions are also considering holding separate strike ballots over pay.
One of them, Unite, which represents engineers, is already balloting its hundreds of members at the company over pay and rest-day working payments, with the result due next week.
In a joint statement issued last week after the breakdown of pay talks, the unions claimed: “ScotRail has continually failed to engage in any productive way with the trade unions."