A large window at The Bluebird on Cardwell Road was smashed sometime on Sunday night into the early hours of Monday morning.
The pane, on the Tarbet Street side of the coffee shop, was badly damaged, pictured, and is due to be repaired this week.
The windscreen of a nearby works van was also damaged around about the same time and there have been reports of cars in the west end of Greenock being targeted too.
Police say they are aware of the incident at The Bluebird Cafe and are investigating.
It is being treated as vandalism and anyone with information is urged to get in touch. Sergeant Laura Stewart, from Greenock police station, said: “We received a report on Monday morning about the cafe.
“Staff came into work and reported that the window had been smashed.
“We are enquiring into it.”
The Bluebird dates back more than 70 years and is famed for its home-made ice cream, so much so that when the business was put on the market four years ago the secret recipe was included as part of the sale.
It was taken over shortly after the operators at the time decided to retire.
Any eyewitnesses or anyone with information about the vandal attack can contact police on 101 or call Crimestoppers anonymously on 0800 555 111.