Ms Devlin was awarded the 2012 Royal Society of Literature's VS Pritchett Memorial Prize at a gala event in London.
This annual prize was founded by the RSL at the beginning of the new millennium to commemorate the centenary of VS Pritchett, an author widely regarded as the finest English short-story writer of the 20th century.
The judges of this year's prize were the novelists Jane Gardam and Penelope Lively and short story writer Aamer Hussein.
Ms Devlin's winning story, 'Singing Dumb', is about a young girl in rural Ireland in the 1930s who is looking after her three-year-old brother who is run over by a car.
"It was inspired by a true story about a tragedy in my mother's family," she said.