Primary schools have the highest number of teachers stagnating in the same job group.
Teachers Service Commission (TSC) Chief Executive Officer Nancy Macharia said the bulk of those affected are 82,524 teachers under Job Group C1.
She said promoting them alone would cost the government Sh16.7 billion.
Speaking on Tuesday before the Education Committee of Parliament, Ms Macharia said the commission has tried to move teachers in their roles. "The commission has implemented its policy directive to achieve at least 5 per cent representation of teachers with disabilities in every promotion cycle, ensuring compliance with national disability inclusion frameworks," she said.