Schools should carry out an audit of parents' skills and qualifications and seek to use them to improve results, according to Ofsted.
Parents' specialist knowledge could be utilised in driving up standards, but is being "underused" by schools, a report from the watchdog recommends.
In Schools and Parents, published today, Ofsted says schools should "consider auditing, and then using more widely, parents' skills and specific expertise as a resource to improve the school".
The recommendation comes weeks after the watchdog announced plans to set up a survey section on its website, allowing parents to rate their child's school and potentially trigger an inspection.
Russell Hobby, general secretary of heads' union the NAHT, said he was unsure about formally auditing parents, but said many would be keen to be more closely involved.
"Parents often want to know more about how they can contribute and build on what the school does," he said.
"I'm not so sure about formal audits of skills, though. Often it's the simple things that count the most - taking an interest, reading with younger children."
The report says: "In the few cases seen where the schools said that parents had contributed or initiated ideas for strategic improvement, and these ideas had been taken forward, they had been successful.
"Although parents often worked helpfully alongside staff (especially in the primary schools visited), the various skills, qualifications, experience and insights of parents were underused to enhance the schools' provision and curriculum."
Examples of parental assistance highlighted in the report, drawn up following 47 visits to schools in 2009 and 2010, included listening to pupils reading, helping out with drama productions, leading choirs and managing sports teams.
Ofsted also refers to bilingual parents leading language classes or translating, and parents describing their jobs at careers events or arranging work experience placements for students.
Parents should be given greater input in setting their children's academic targets, the report goes on, adding that they displayed a "better understanding of the assessments that schools made about their children" than when Ofsted last reported on the issue in 2007.
"The schools usually gave them accurate, timely information and opportunities for discussion with staff," the report says. "However, input from parents directly into setting pupils' academic targets was less common.
"All the schools visited gave parents guidance about how to help their children to learn at home. This differed widely in style and quality across the schools visited."
Inspectors found parents with children attending primary school tended to be more involved than those with secondary-age children.
"Parents of younger children therefore saw teaching and learning happening, which made them feel closer to the process," the report says.
Overall, the schools surveyed were "welcoming to parents, and the parents noted improvements in the schools' relationships with them".