Carol Harper, 57, was employed at King Edward VI high school in Westway, Stafford, when the accident happened in May 1999.
The maths teacher was going down some stairs on her way to invigilate a GCSE exam when she slipped and fell down eight steps, fracturing a bone in her left ankle.
Mrs Harper, from Stoke-on-Trent, was off work for a year and eventually had to retire. She claimed her local authority - Staffordshire County Council - was to blame for failing to ensure staff safety.
At the High Court last Thursday, Judge Wilkie QC found that the council was in breach of the 1992 Workplace (Health, Safety and Welfare) Regulations and ordered it to pay Mrs Harper pound;44,650.
The authority, which agreed the damages, denied liability. It is considering whether to appeal.
Both Mrs Harper and the National Association of Schoolmasters Union of Women Teachers, which backed her case, were pleased with the outcome.
Mrs Harper told The TES: "There will be people who say that the payout was too large for the injury I suffered, but if it happened to them in identical situations, what would they do?
"I was 53 at the time of the accident, earning around pound;23,000 per year. Multiply that by the seven years for me to reach 60, and the figure is pound;161,000. The payout is therefore short of what I would have earned.
"I certainly did not ask for the injury and no amount of money can compensate for what I have lost - doing the job I loved to do."
Some of the award will help pay off debts since the accident.
At the hearing, the council said school notices told children not to take food from the dining room, teachers monitored the situation and doors were locked between the canteen and stairs at lunchtime. But on the day of the accident, the doors were left unlocked.