Leanne Wilkinson, who was 18 when Springwell Engineering in Newcastle dismissed her, was told she was too young for the job, and that they needed an older person with more experience.
The tribunal ruled in her favour, rewarding her £16,081.
This is the first time since the 2006 age discrimination laws came into force that they have been properly tested in relation to young workers, according to Nexus, the law firm that represented Wilkinson.
Last year Megan Thomas, 20, successfully took her employer to court on similar grounds, but the employer did not contest it so the issues were not debated, which meant it could not be used as a test case.
In Wilkinson’s case, the tribunal said the employer had relied upon a "stereotypical assumption that capability equals experience and experience equals older age....age was the predominant reason for the decision to dismiss".
