It monitors how young people interact with friends and family online and through messaging apps.
It uses AI to evaluate a child's mood so it can offer advice or encourage them to talk to trusted adults.
The app is designed to offer help and support especially if children are about to share sensitive data or send an upsetting message.
"The digital world is a fantastic place for people to learn and share, but we know many young people struggle to find a healthy online balance, especially when they get their first phones," said Alice Webb, director of BBC Children's, in a statement.
Ms Webb said the app would act as a "helping hand" to guide children into developing good habits when using their first phone and avoid some of the potential pitfalls of digital life.
The app is built around a special software keyboard that pops up when kids type messages and monitors the tone of the words being typed and language used.
The Own It app also has its own content that aims to help children manage the amount of time they spend looking at their screen and passes on other advice about responsible online interaction.
The BBC said the app would also regularly encourage children to talk to parents and guardians about good and bad online experiences and their phone use.
The app has no reporting system that parents can consult to oversee phone use, said the BBC.
The Own It app began development in 2018 and has drawn on input and support from many different child-focused charities and welfare groups.
Partners include the Mental Health Foundation, the Anti-Bullying Alliance, the NSPCC, the Diana Award and Childnet.
The app is being launched against a background of research which shows how concerned some parents are about phone use among their offspring.
One study published in August suggests half of all UK parents want mobiles banned in schools to help regulate use.
Separate studies suggest teenagers are not damaged by prolonged screen use but official advice in the UK says parents should tell children to put down their devices in the hour before bed.