The court ruled Thursday in the case of a Danish child-minder who says he was unfairly fired for being fat.
The court said if obesity hinders "full and effective participation in professional life," it could count as a disability. Discrimination on the grounds of disability is illegal under European Union law.
Karsten Kaltoft worked as a child-minder for 15 years for the Municipality of Billund in Denmark, before he was dismissed in 2010.
Kaltoft, who weighed 159 kilograms (350 pounds), says he was fired for being obese, a claim his employer contests.
The court says it was for Danish courts to decide whether Kaltoft's obesity constituted a disability.