The West Yorkshire Playhouse in Leeds is trying to change that with a "diversity internship" programme. Five one-year training opportunities have been created for people from African, Caribbean, Chinese and Asian backgrounds.
"Two high-level theatre conferences last spring concluded that institutional racism exists in the theatre world and that it should be addressed," said Maggie Saxon, managing director at the West Yorkshire Playhouse.
"The Playhouse is, after Stratford, the largest theatre in the regions. It's very much a flagship, so we have a responsibility to redress what we see as an employment imbalance."
The scheme is being run in collaboration with the Creative Industries Development Agency. CIDA is responsible for finding the funding and support, training and mentoring programmes.
"We were particularly looking for people who had hit a glass ceiling in their careers," said Ms Saxon. "Getting into our industry is difficult enough. We advertised for the interns and networked in the target communities. We had five applicants for each post."
The five interns will each have a tax-free bursary of pound;10,000. They are working in graphic design, administration, technical sound and light and the arts development unit. They will have a validation certificate when their training is finished.
"In the past there have been single internships," said Ms Saxon. "But we have introduced a critical mass, that's what is so innovative about this programme. We ensured that there are support networks. We cannot offer jobs at the end, but we will be putting people in the best position to apply for them."
Asha France, a former clerk from Leeds, will be acting as a front-of-house duty manager within a few weeks of starting her internship.
"This is an opportunity for me to bring my Caribbean community to the Playhouse ," she said.
Sarabjit Kohli, an intern from Huddersfield, has fine arts qualifications.