Parents at Todholm Primary School, in Renfrewshire, were told the school would be shut for the next five days after the suspected cases of the new variant.
Two class groups in P1, and another in P2, were self-isolating, Renfrewshire Council said.
In an email sent to parents, it said the decision to close the school until Monday, December 13, was “due to the difficulty in operating the school with reduced teaching and support staff and maintaining an appropriate staffing level for the school”.
And the statement added: “Please be reassured the temporary closure is not a public health issue and the health and safety measures in the school have been confirmed as very robust.”
The outbreak at the school comes after Scotland recorded 23 new cases of the Omicron variant within the past 24 hours, taking the overall number to 71.
Figures published by the Scottish Government on Monday showed there were 3,894 new coronavirus cases recorded and no deaths within the past 24 hours.
The daily test positivity rate was 12.8%, up from 9.6% the previous day.
There were 591 people in hospital on Sunday with recently confirmed Covid-19, up five on the day before, with 43 in intensive care, down two.
A note on the daily figures said the statistics were higher than expected due to a backlog of tests.
First Minister Nicola Sturgeon is giving an update to the Scottish Parliament tomorrow on the new variant.