Ministers have been urged not to drop a Conservative manifesto pledge to get a million more disabled people into work.
Charity Mencap have sounded the alarm after there was no reference to the policy in this week's Queen's Speech, which outlines the Government's legislative programme.
Despite a previous Tory commitment to halve the disability employment gap, the learning disability charity says the employment rate of those with learning disabilities has actually fallen.
Jan Tregelles, Mencap chief executive, said: "For too long people with a learning disability have been forgotten by the job market and overlooked by Government work programmes - despite repeated commitments to the contrary.
"Employment levels have remained woefully low, meaning hundreds of thousands are missing out on the pride, independence and self-worth that a job offers, and instead left isolated facing a life on benefits.
"This doesn't need to be the case."
Mencap says employers such as Legoland and Kew Gardens support their campaign given the success they have had employing people with a learning disability.
The charity is calling on the Government to help 120,000 people with learning disabilities find employment over the next decade, given it believes that 12% of all disabled people have a learning disability.
Ms Tregelles added: "With the Government's commitment to get one million more disabled people into work, we cannot let people with a learning disability be overlooked yet again."
The Conservative manifesto said it would get one million more disabled people into work over the next 10 years through things like flexible working and the digital economy.
It also outlined plans for a holiday on National Insurance Contributions for a year for staff who were disabled or had mental health problems, as well as ex-offenders.
The number of people with a learning disability in work has fallen from 7.1% in 2011/12 to 5.8% in 2015/2016, according to NHS figures.
David Gauke, the Work and Pensions Secretary, told MPs on Thursday that the Government remained committed to the target.
"This Government is committed and remains dedicated to continuing our work in improving employment outcomes for people with disabilities and health conditions," he said.
"We have made a commitment to get one million more disabled people into work over the next 10 years.
"This will enable them to enjoy the benefits that we know good work brings."
But Mark Atkinson, chief executive of disability charity Scope, said it was a missed opportunity not to have brought forward legislation to help meet the target.
"This omission has a very clear impact on progress needed to tackle the disability employment gap," he said.
"Disabled people have been cut out of the social care debate and now they have been removed from the Government's employment policy.
"We urge the Government to set out how it intends to tackle this burning injustice, setting clear timelines for when and how it will deliver its promise."