The situation at the pre-school centre at Donaldson's School, in Lithlithgow, comes after a West Lothian Council decision to drop it from its list of partnership nurseries. Only partnership nurseries can offer parents the part-time free nursery places scheme put in place by the Scottish Government.
Campaigners argue the decision penalises working families as council nurseries are unable to provide the same flexible services.
Judy Vickers, one of the parents leading the protest, said: "Removing the provision of funded places from Donaldson's means there is only one private nursery in Linlithgow able to offer funded places and it simply does not have the capacity to meet demand."
Parents will now appeal the decision.
A West Lothian Council spokesman said: "A planned tendering process was recently carried out to secure a partner private nursery to provide additional mainstream pre-school capacity in the Linlithgow area. Donaldson's Nursery was unsuccessful in their tender and, as this process is currently in the legal standstill process, it is not appropriate to comment further."