A van and two cars were torched in the town over the weekend.
The incidents took place in Hawthorn Street, Newlands Road and Ochil Street on Saturday.
A Police Scotland spokesperson said: “Officers at Grangemouth received reports of deliberate fires set at three vehicles in Ochil Street, Newhouse Road and Hawthorn Street in the town just after midnight on Saturday, November 13.
“Enquiries are ongoing.”
Contact 101 and quote 0109 of November 13.