A university official said students who took the test did not have a basic grasp of English and “lacked enthusiasm”.
The country’s education minister however said she found it hard to believe not a single candidate managed to pass.
Etmonia David-Tarpeh said she would be meeting with officials from the university to discuss the dismal failure rate.
She acknowledged there were weaknesses in the education system in Liberia, which is still recovering from a civil war which ended 10 years ago, but said she had her doubts that no one could have passed.
A spokesman for the university said it would be standing by its decision, and that the government needed to do more to improve students’ knowledge of English.