RSA Academy, in Tipton, has temporarily closed until December 1 while Wood Green Academy, in Wednesbury, has closed until December 2.
In both cases, a number of coronavirus cases has resulted in "large numbers" of students and staff being sent home to self isolate.
Pupils at both schools will be taught remotely at home through virtual lessons and online learning support.
In a statement on the school's Facebook page, the RSA Academy, which has 1,088 pupils, said: "Unfortunately, from Monday, November 23, we will have insufficient staff to operate the school safely due to the notification of several of our students testing positive [for] Covid, resulting in large numbers of staff and students being sent home to self isolate.
"After careful consultation with the local authority [Sandwell Council] and Public Health, and with the safety of the academy community being our absolute priority, the decision was made to close the school for a period of time.
"Students in Year 11, 10 and 8 must now self isolate until November 30, we will keep you updated if this changes. Unless the students are showing symptoms this does not affect anyone else in the households.
"If anyone in the household has symptoms they mist get a test and everyone in the household must self isolate."
In a statement on Wood Green Academy's website, the school, which has 1,459 students, said: "Unfortunately, from November 23 we will have insufficient staff to be able to operate the school safely due to the notification of positive Covid cases resulting in large numbers of students and staff needing to self isolate.
"After careful consultation with the local authority [Sandwell Council] and Public Health, and with the safety of the academy community being our absolute priority, we have decided to close the academy and we will reopen on Wednesday, December 2.
"However, please check the academy website and email for updates as this may be subject change."