A teacher at one of Co Down's top schools was overlooked for a temporary promotion because she worked reduced hours, the Equality Commission said.
Catherine McCormick settled her indirect sex discrimination case against Assumption Grammar school in Ballynahinch for £5,000.
She worked three days out of five following her return from maternity leave.
"When a colleague was appointed temporary head of English, and I was not considered because I was working part time, I thought it was unfair to be denied the opportunity to be considered for this temporary promotion and the chance to gain that experience," she said.
"I understand that the demands of the post would mean working full-time, but I wasn't given this option."
The school had been very accommodating of her flexible working arrangements, which she needed because of child care responsibilities.
She has been teaching at Assumption since 2007.
"I love my job and am happy at the school, so I'm pleased that a new co-option policy has been put in place which will ensure that opportunities for career enhancement are dealt with on a formal and procedurally correct manner," Ms McCormick said.
In settling, Assumption recognised that it did not give Ms McCormick an opportunity to apply for the position and disadvantaged her as a part time/flexible worker.
The commission said the school's board of governors regretted the upset felt by Ms McCormick and looked forward to continued good working relationships.
It said it confirmed that there will be no disadvantage to her due to the fact that she was unable to avail of the acting up experience, nor will she be victimised in any way.
The board of governors will liaise with the Equality Commission on appropriate training in recruitment and selection with specific focus on part-time workers.
"This is a good result all round – one of the main reasons we support cases is to effect change," Anne McKernan, head of legal services at the commission, said.
"While Catherine missed out on this opportunity, she has been able to secure a change in policy and practice that will benefit other teachers into the future. It's good that this has been resolved productively and amicably.
"We're publicising this to remind all employers of the difficulties and dangers of disadvantaging people on flexible or part time working arrangements, even unintentionally."
In Northern Ireland, 39 per cent of female employees work part-time compared to 9 per cent of male employees, and 82 per cent of part-time employees are women.
Because of the high concentration of women in part-time jobs, any measure which excludes part-timers from a particular post or promotion is likely to have a more adverse effect on women, and that's why it may amount to indirect sex discrimination, Ms McKernan said.
