The pupils, all aged between five and nine, are planning to take Leeds City Council to court over plans to close Cookridge Primary, and have just been granted legal aid to do so.
If successful, the case could have wide-ranging implications for education authorities attempting similar closures of successful schools.
The council wants to merge the school with nearby Tinshill primary, due to what it claims is a glut of surplus places.
However, headteacher Stuart Tomlinson insists Cookridge is already full to capacity. The children have applied for leave for a judicial review and are awaiting a High Court decision on whether they have a strong enough case.
Cookridge, which recently received a good Office for Standards in Education report, has around 300 pupils on roll, but the LEA claim it can accommodate 420.
A spokeswoman for Leeds said the authority was confident it would win any court case. She said: "The authority plans the provision of school places very carefully indeed."