Kingsmead School, in Kings Avenue in Hednesford, shifted lessons online on Friday as they carried out a deep-clean to keep students safe.
It is not known how many students were showing symptoms of scarlet fever, which is caused by Strep A which parents have been warned about.
A statement on the school's Facebook page said: "We have a great deal planned for the final week of school before Christmas and we don't want anyone to miss out.
"With a notable number of students absent (on Friday) with symptoms matching those of Scarlet Fever, we have taken the decision to close as a precautionary measure. This will allow us to deep-clean the school and reduce the opportunity for infections to spread, so that we can have an uninterrupted Christmas week.
"Thank you for your understanding and for the messages of thanks and support that you have sent to us today. For further information please refer to the letters that have been sent out via ParentPay."