The inquiry, by the All Party Parliamentary Group (APPG) for Looked-After Children and Care Leavers, is the third national probe of the care system for children in less than a year.
Conservative MP Craig Whittaker, who chairs the APPG, said: “It is vital that looked-after children and care leavers receive what the law says they should.
“There are a range of entitlements for those in care, including having a care plan developed with them, being given the right information to make decisions, having social workers speak to them alone when they visit, or being able to access financial support.
“We want to hear from as many people with experience of the care system as possible.”
The latest inquiry comes on the back of two others relating to care in the last 12 months.
An ongoing inquiry by the Association of Directors of Children’s Services (ADCS), got under way in October. It is looking at how to better serve the needs of young people in the care system, how to improve placement stability, and how to secure more permanent placements for children who are not adopted.
Meanwhile, the findings of the Care Inquiry, launched by a group of eight charities last year, were published last month.
Natasha Finlayson, chief executive of The Who Cares? Trust, which provides secretariat support to the APPG, said the MPs' inquiry is seeking to hear from as many young people with experience of the care system as possible.
“This is their chance to tell the government whether they get the information they need, the support they have a right to, and whether people really listen to them before making decisions about their lives,” she said.
It also wants to hear from care leavers and professionals.
The inquiry will collect evidence until 17 August, with the findings due to be published during National Care Leavers’ Week, which starts on 24 October.
In a separate development, the National Children's Bureau has produced fresh guidance to help councils fulfil their duties for children in care.
Putting Corporate Parenting into Practice is aimed at councillors and senior officers in local authorities across England. Children's minister Edward Timpson has today written to all lead members and directors of children's services urging them to make full use of the guidance.
"Recent high-profile cases in Oxford and Rochdale have confirmed what is at stake if local authorities fail children in the care system", said NCB chief executive Hilary Emery. "As corporate parents, councils must ensure that public care is of the highest possible quality".