The Rail, Maritime and Transport union (RMT) and the Transport Salaries Staffs Association (TSSA) claimed ScotRail planned to reduce the number of ticket windows and staffing at eight stations.
The unions said they were at Edinburgh Haymarket, Glasgow Queen Street, Aberdeen, Dundee, Inverness, Paisley, Perth and Stirling.
It is understood between six and 15 jobs are threatened.
ScotRail said there would be no compulsory redundancies and called for further talks.
RMT Scottish organiser Mick Hogg said: "They are doing away with jobs to save money and passengers will suffer.
"I'm sending a report to the union's general secretary recommending a ballot for action."
Many tickets can be bought at ticket machines at stations or online, but some are only available at ticket offices at stations with ticket barriers, including discount fares for various types of passengers including children.
In a joint statement, the unions confirmed: "Both unions are committed to working together to resist the proposals put forward by ScotRail and are preparing to ballot our respective members to resist their implementation."
It said the TSSA had requested that ScotRail reviewed its ticket offices/travel shops last year because of "chronic understaffing".
The union said many of its members had raised issues around "workload, work/life balance and highlighted the unavailability to take lieu days owed to them".
The unions said: "As a result of the review undertaken by the company, ScotRail have decided to ignore the concerns raised by union members in the travel shops and have instead decided their preferred means of addressing issues around workload and lieu days is to reduce staff and close windows.
"This is wholly unacceptable to both RMT and TSSA.
"Both unions have been sent copies of proposals which reduce staffing levels within ScotRail travel shops and remove some of the higher graded posts.
"Neither union have agreed to any individual or set of proposals, which currently are being put to local level for consultation.
"We will resist any job losses and imposed roster changes – and we deplore ScotRail’s blatant decision to ignore due process and railroad through change."
Scottish Conservatives transport spokesman Jamie Greene said: “Strike action should only ever be considered as a last resort and all parties should be encouraging dialogue between ScotRail and the unions to resolve this matter.
“Whilst it is important that ScotRail is able to review its structures and modernise its practice, it is equally vital it does so in a way that does not disproportionately impact jobs.
“Whenever possible, ScotRail must ensure that any redundancies come with a fair package and the offer of a new placement within the organisation."
ScotRail head of customer operations Phil Campbell said: “Our proposals are about meeting the changing needs of our customers and the way they choose to pay for their journey.
“ScotRail operates a very clear policy of no compulsory redundancies – everyone who currently has a job will still have one.
“We’re disappointed the trade unions have not engaged with the clear need to change but instead threaten industrial action.
“We have suggested to the trade unions we hold further local meetings to allow meaningful discussions on this matter to take place.
"This is in line with the agreed procedures.”
ScotRail said the ticket office review requested by the unions had shown the way passengers bought tickets had significantly changed but ticket office staffing was based on buying patterns nearly 30 years ago.
It said it had to change because more and more people were using ticket machines or buying online.
The train operator said various proposals were made to the unions that ensured opening and closing times remained unchanged.