Bus safety group Busk wants Vale of Glamorgan Council director Rob Quick to resign claiming he has failed to act on recommendations made by a jury.
Stuart died after the bus crashed into a tree
It follows claims that there have been no policy changes since Stuart Cunningham-Jones, 12, died in a crash near Cardiff.
An inquest jury recommended such buses have a supervisor but Busk says the council has not acted on this.
The council said it was fully complying with its commitments and had the "utmost confidence" in Mr Quick - director with responsibility for school transport.
The resignation call comes a day after transport tender documents seen by BBC Wales showed the council still said drivers, and/or escorts, should supervise children on buses taking them to or from school.
The inquest in Cardiff in January heard how during the minutes leading up to the crash, Norman Davies, the driver of Stuart's bus, was repeatedly distracted by a group of boys.
And giving evidence at the hearing, Mr Davies recalled how seconds before the bus crashed into a tree he looked down to see a boy's hand on the steering wheel.
The jury returned a verdict of accidental death but it also recommended that all buses carrying pupils should have a supervisor on board.
Busk - Belt Up School Kids which campaigns for better bus safety - has now accused the council of ignoring the inquest jury.
The jury's comments were not made public at the inquest but were later sent to the Vale of Glamorgan council by the coroner.
The recommendations included all school buses having trained and qualified escorts, and that a liaison officer be appointed by the local authority to monitor behaviour on buses carrying schoolchildren.
Stuart's parents, Joanna and David, have described the jury's recommendations as "common sense".
More than 30 children were injured in the crash near Ystradowen
Chris Howard, chairman of Stuart's Campaign, a group campaigning for pupils' safety said: "If re-tendering is going ahead, we would be alarmed and would seek reassurance from the Vale education authority at the next meeting of the consultative committee on Tuesday."
But the council has said a group had been set up to look at school transport and part of its work would include a review of school bus contract conditions.
Council Chief Executive John Maitland Evans said: "Following the receipt of the coroner's letter in early February, the council has acted promptly and effectively to progress consideration of the issues raised at the inquest.
"The consultative group, chaired by Mr Quick, is a key part of the process. It met first in mid-March and meets for the second time next week.
"The coroner acknowledged that the council was willing to discuss a way forward with all parties, and the group includes parents, school representatives, including teachers and governors, bus operators and an official of the Welsh Assembly Government.
"It is intended that the views of the group will be fed into a planned review of school transport later this year.
"The current issues raised by Busk relate to a small percentage of current school bus contracts which required renewal for the next school year as a matter of urgency.
"The council is confident that it is fully complying with its commitments following on from this tragic accident and the subsequent inquest, and has the utmost confidence in Mr Quick in terms of his current and future management of school transport issues."