Several people at Monifieth High School have tested positive for Covid-19.
Most pupils only returned to the school part-time less than a fortnight ago.
However, already some have been asked to isolate after being identified as close contacts of those who have contracted the virus.
The infections were said to have been as a result of contact outside school.
Covid in several schools
Several schools in Tayside and Fife have already been affected by Covid cases since the phased returned began on February 22.
This has meant pupils who have had to isolate missing yet more class time, after weeks of remote learning.
A spokesman for Angus Council said: “A small number of coronavirus cases linked to Monifieth High School have been confirmed as a result of out of school contact.
“Any close contacts have been identified and asked to self-isolate.”
A small number of coronavirus cases linked to Monifieth High School have been confirmed as a result of out of school contact.”
Last week a nursery in Dunfermline closed due to six cases linked with it. Several staff members at Pitreavie Kindergarten were asked to isolate.
Strathmore Primary School, in Forfar, is also among schools where pupils have had to stay at home.
And Perth and Kinross Council revealed last week that more than 200 pupils and staff members across its schools had had to isolate since schools started to reopen.