The 07.44 Greater Anglia service from Saxmundham to Lowestoft, which many students rely on to attend Lowestoft Sixth Form College, has been cancelled as much as four times a week in recent weeks.
Julia Ewart, a Saxmundham Lib Dem politician, arranged a meeting with parents after their children had been left stranded in the mornings making the journey to school.
She said: "The students worry about attendance and, importantly, missing classes and information at this intense time.
"Walking into class half way through does not go down well with teachers.
"There is a feeling by train staff that the service, which starts at Saxmundham, will be cancelled totally. Then what?"
Approximately 20 students make the 50-minute journey to Lowestoft from Saxmundham station every day, with a pass costing £92 a month.
However, cancellations frequently result in parents having to make back-up plans for their children.
Mrs Ewart criticised Greater Anglia for the cancellations, saying the firm need to consider their "civic responsibility" of ensuring students are able to attend the school and receive an education.
She added: "All services need to up their game and meet the expectations of their customers.
"Our young have been tempted by the magnificent facilities at Lowestoft, but given the train service they pay for is so unreliable, they are really up against it to fulfil the commitment expected of them."
Greater Anglia said in a statement: "We're sorry for the inconvenience caused to customers when any of our services are cancelled. When the 07.44 Lowestoft to Saxmundham service has been cancelled, we have advised customers to catch the next train at 08.15, which arrives at Lowestoft at 09.06.
"Unfortunately, recently we've had to cancel services after trains have been severely damaged due to collisions on the line with trees and animals. We advise any customers affected by the cancellation of this service to claim Delay Repay compensation."
