Parents and charity workers will accuse Sheffield Council of failing children with special needs as they march through the city this weekend.
Campaigners say the authority is using finances rather than needs to shape its policies for youngsters with autism and other learning disabilities.
They say children are missing out on places at special schools because the council is taking too long to set up education, health and care plans.
The plans are legally binding agreements that cost councils money.
These delays, campaigners say, force parents to go through months and years of appeals and tribunals to get the help their children require.
And they have accused the council of changing its policy to save money despite there being no cut to the Send budget.
The council admits it has made mistakes, which the authority this week said it 'truly' regretted.
But city charity Sparkle Sheffield has organised a protest to highlight the issues. Campaigners will march from Devonshire Green to the Town Hall from midday on Saturday.
Sparkle is also running a campaign called 'Stop The Abuse',
Charity founder Liesje Dusauzay said she had been 'inundated' with parents and carers because of the council's 'failings'.
She said the authority had been 'letting disabled children and their families down' at a time when other services were being closed or scaled back.
"We in Sparkle Sheffield have endeavoured to engage with the local authority, including at the highest level of Send, to repeatedly draw their attention to these grave concerns, but things have not gotten any better.
Parents and carers in the city, asked us to support them to make public and transparent their concerns and to facilitate their protest against the institutional harms and abuses that have been happening in Sheffield, with calls for it to cease.
"Disabled children and their families in our city not only deserve but are entitled to better."
A petition calling for council leader Julie Dore to tackle the problems so far has almost 2,000 signatures.
One family who will join Saturdays march are the Mills of Handsworth.
Husband and wife Steve and Emma are still trying to get a plan for their son Sam finalised after a year of stress.
Sam, seven, was diagnosed with autism two years ago, but has gone through reception and year 1 at a standard school, despite regularly hitting out at people, running from class and screaming. He has since been diagnosed with severe anxiety and depression.
He has been placed in a small nurture unit, which has helped, but Sam's parents want him to be placed in a special school that can better meet his complex needs.
The new school year has now started and Sam still has no such provision in place.
Emma, 34, said she had to rewrite Sam's plan herself after the initial council draft came back full of errors. She accused the council of purposely delaying a decision on his placement for this year.
"Our current position is that we have no suitable provision for Sam for the new school year," she said.
"We have a disabled child suffering extreme anxiety and depression who has no idea of when he will go to school or where.
"Despite me asking repeatedly for the department to provide an interim solution for my son such as a home tutor or one to one in mainstream school so that he can continue his education whilst they sort out a final placement, they have ignored every request from me to sort this out.
"I have had to give up work because of the stress his is placing on all our family. Not only do I have to care for my disabled child with high needs I have to read all of the law on education, I have to constantly write reports and chase answers to emails."
Emma said her family was not the only one facing a similar situation.
"There are Sheffield children with worse stories who have been forced out of education completely for years, where parents are forced to homeschool as the local authority refuses to provide the child with suitable provision," she added.
"We care about our children and we cannot stand by and see them suffer any more."
The council said it was working to review its Send provision following national changes in 2014, and no decisions had been made regarding service changes or closures.
It plans to consult parents, schools and providers.
Executive director of people's services Jayne Ludlam said: “We are continuing to work hard to bring about improvements in assessing, supporting and implementing the right provision for children with special educational needs and disabilities.
"We recognise we have not got this right in every case in the past, or currently, and we truly regret this.
“We want to reassure families that we are committed to improving outcomes for children with special educational needs and are working hard to improve services at all levels."
Ms Ludlam added: “We regularly meet and work with parents’ groups and this has provided valuable insight.
"We will continue to listen to parents and work with them to improve our services and support across all schools. We would always want to work in partnership with families and continue to do so.”