Ten schools in the Bedford Borough area and a number across Central Beds were closed on Tuesday due to strike action by teaching staff.
Parents were being advised to check their school websites for updates on closures and year groups affected as headteachers worked to plan for potential disruption.
The action came as members of the NUT and NASUWT teacher trade unions called on members to take a one-day strike action. The planned action was in relation to ongoing disputes about pay, pensions, working conditions and jobs.
Among middle schools affected were Harrowden, Lincroft, Robert Bruce, Marston Vale and Newnham.
A letter to parents of Lincroft pupils said the decision to close was taken to ensure the health, safety and well-being of students and were aware of the disruption to families.
The school was open to employees not taking action.
Westfield Middle School was among the partial closures, with pupils in years 5 and 6 having a day off, and Oakley Lower was also affected.
In a letter to parents on the Westfield school’s website, the headteacher said: “We do not take this decision lightly, and I understand the disruption this creates for families, but I hope that by giving you prior notice, we have given you adequate opportunity to arrange childcare, where necessary.”
A Bedford Borough Council spokesperson said they had expected about 10 schools to close on the day, with another 11 that may be affected by the action.
Sixteen schools were closed across the whole of the Central Bedfordshire Borough area, affecting lower and middle pupils.