The incident happened at Bathgate Fire Station in West Lothian at about 00:30 on Wednesday.
A fire community vehicle was damaged as well as eight cars that belonged to the firefighters.
Police have appealed for any witnesses to the "mindless act of destruction" to come forward.
Ch Insp Paul Cameron said: "This has been a mindless act of destruction targeting the local fire service while the crew was out assisting the community.
"In addition to the damage sustained to fire officers' cars, a community fire vehicle was also damaged and will require repair, taking the vehicle out of service which deprives the community of this resource.
"We are keen to hear from anyone who remembers seeing anything suspicious around the station in the early hours of Wednesday morning.
"Similarly, anyone with any further information relevant to this investigation should contact police immediately."
Vandals who smashed fire station windows and damaged several vehicles while firefighters were out at an incident are being sought by police.