Natasha Gregory, former head of art at the Wordsley school, in Dudley, west Midlands, was found guilty of unacceptable professional conduct by England's General Teaching Council.
It heard that she substituted work by some students for that by other pupils and teachers. She was also found guilty of altering one pupil's work she believed to be sub-standard to "bump up" grades.
The disciplinary hearing was told this week that Miss Gregory kept a bank of work from previous years.
Claire O'Connell, art teacher at Wordsley, said: "She disclosed that she kept a bank of work to substitute into pupils' work which wasn't up to standard.
"In April 2004, an external moderator came into the school. I realised that a piece of work - a 3D hat - attributed to pupil A was not his work and I recognised it from the bank.
"Miss Gregory also displayed my work in place of another pupil's and asked me not to mention it to anyone."
Claire Stafford, a former art teacher who was mentored by Miss Gregory, said: "During my observations of Miss Gregory's Year 11 class, I became concerned about her involvement in pupils' work.
"Pupils frequently complained that their own work had been substituted."
Miss Gregory was suspended in July 2004, after other teachers at the school raised the alarm with head Michael Lambert. Miss Gregory later admitted substituting a pupil's work and resigned in October 2004. She said: "During the time for which the allegations have been made, I was in a very poor mental state. I was aware of the serious nature of my actions but I panicked.
"I wanted these pupils to leave with the grades they should have achieved.
For some, art would have been the only GCSE they got."
Bradley Albuery, presenting officer, said Miss Gregory's actions went "right to the root of trust".
Paul Blake, her National Union of Teachers representative, said: "The six-month suspension is, of course, accepted but felt to be unduly harsh."
Chris Cook, who chaired the hearing, said: "In view of the substantial mitigating factors, we have decided not to prohibit her from teaching in the future, but to mark the seriousness of her actions with a period of suspension and a condition that she be fully fit to teach before she returns."