A 15-year-old boy has been remanded in youth detention after being charged over the stabbing of two pupils at a school in Dulwich.
He was refused bail at Camberwell Magistrates Court and will appear before a judge again next month.
He is accused of attempted murder, grievous bodily harm and possession of a bladed article.
The two victims, both 15, are being treated in hospital. One remains in a critical condition.
The attack happened at Kingsdale Foundation School in south London on Thursday shortly before 15.30 GMT, and pupils were kept inside buildings as emergency services dealt with the situation.
The school reopened on Friday.