Jo Bowen, who taught at Kesgrave high in Ipswich, drank so much at one party that she vomited and passed out, England's General Teaching Council heard. Ms Bowen faces several charges of unacceptable professional conduct, which she denies.
Nigel Burgoyne, deputy head of the school, told the disciplinary panel that Ms Bowen organised a party after a school production of Romeo and Juliet in December 2002. "She encouraged sixth-formers to drink alcohol. She and students were drunk and she was observed in the toilets vomiting and later passed out."
Rachel Jones, a teacher, said that at midnight Ms Bowen had told everyone to clear up. "Then when the others had gone, some sixth-formers came out of hiding in the bushes in the car park and the party carried on," she said.
Stuart Race, a drama teacher, said pupils were drinking at the party, which was held in a scout hut. "Ms Bowen told me afterwards that the party had gone on until 5.30am," he said.
He had not wanted to attend the party and had only done so to avoid confrontation. At a party following a production of Grease in 2001 he had told Ms Bowen he wanted to leave at about 2am. "She was very drunk and told me she was the head of department and so she made the decisions," he said.
George Thomas, the headteacher, asked his deputy to investigate the allegations in September 2003. He said after the GTC hearing that Ms Bowen was no longer teaching and had no intention of returning to the job.
Ms Bowen told the hearing that she was shocked when she learned of the allegations.
She said the parties were organised and paid for by parents and although she admitted taking alcohol to them and drinking, she had not been drunk and had not passed out.
"At the Romeo and Juliet party there were students drinking and being sick.
I was only a guest. I was not responsible for their drinking," said Ms Bowen.
"I am most saddened by these allegations. I spent an enormous amount of time with my students, over and above normal working."
Other allegations against Ms Bowen include forging pupils' signatures on their exam papers, failing to keep proper financial records of expenses for a school show and failing to ensure the right A-level syllabus was taught.
The hearing was adjourned.