The GCSE exam regime in England will be reformed so that qualifications match the standards in the world's leading education systems.
Pupils starting secondary school in England in September will be expected to study the key academic subjects forming the English Baccalaureate (Ebacc) at GCSE under the reforms being set out by Education Secretary Nicky Morgan.
The reforms will see the grade considered to be a "good pass" at GCSE set at the equivalent of a current low B or high C.
The Government has also appointed school behaviour guru Tom Bennett to draw up plans to help teachers address problems of "low level disruption" in classrooms which can lead to pupils losing up to an hour of learning time a day.
Under the plans, pupils starting secondary school in September will study the Ebacc subjects - English, maths, science, history or geography, and a language - at GCSE in 2020.
Only a "small minority" of pupils for whom the Ebacc "will not be appropriate" will not take the exams.
The way GCSEs are graded is changing from the current A-U system to a nine-to-one scale.
A "good pass" - currently a C or higher - will be set at grade five under the reforms, which will be outlined by Mrs Morgan in a speech at the King Solomon Academy in north London.
This is comparable to a low B or high C and "raises the bar for performance across the board", the Department for Education said.
It brings the benchmark broadly in line with the performance in countries such as Finland, Canada, the Netherlands and Switzerland.
Mrs Morgan said: "As part of this Government's commitment to social justice we want every single person in the country to have access to the best opportunities Britain has to offer - starting with an excellent education.
"This means ensuring children study key subjects that provide them with the knowledge they need to reach their potential– while setting a higher bar at GCSE so young people, their parents and teachers can be sure that the grades they achieve will help them get on in life.
"And it means giving new teachers the training they need to tackle low-level bad behaviour which unfairly disrupts pupils' learning."
Mr Bennett will lead a new group to develop better training for teachers to tackle disruption caused by naughty children.
School inspectors Ofsted found that misbehaving children were having a significant impact on their fellow pupils by taking up teachers' time through behaviour such as swinging on chairs, playing with mobile phones, making silly comments or passing notes in class.
Mr Bennett said: "Behaviour has been the elephant in the classroom for too long, and the amount of learning time lost because of disruption is a tragedy.
"At present training teachers to anticipate, deal with and respond to misbehaviour is far too hit and miss - great in some schools and training providers, terrible in others.
"Parents and children deserve safe, calm learning spaces, and teachers deserve to be equipped with sensible strategies that maximise learning, safety and flourishing. I'm delighted to lead a group which will offer advice on doing just that."