Cases were confirmed at St Peter’s Primary School and Nursery in Galashiels last night.
A Scottish Borders Council spokesperson said: "Yesterday evening a single positive COVID-19 case was confirmed within the school community which resulted in the P5/P6 composite class being asked to self-isolate.
"Late last night a small number of other positive cases were notified to the school, affecting a number of different class groups.
"As a precaution, and to allow NHS Test and Protect to carry out full contact tracing and identify if there is any connection between the cases, the council has taken the decision to close St Peter’s Primary School and nursery today (Wednesday, June 9).