Pupils will lose marks for poor spelling, grammar or punctuation in GCSE exams from September.
The stricter rules are part of a policy announced this week by Michael Gove, the Education Secretary.
Ofqual, the exams watchdog, announced that pupils will be tested in end-of-course exams from summer 2014.
Questions will be set on the whole of the syllabus. This will start in geography from this September, maths from November and history and English literature from September 2013.