Protecting our Students in Schools Act of 2021 This bill prohibits the use of corporal punishment in schools that receive federal funding. Specifically, the bill authorizes the Department of Education (ED) to take specified actions (e.g., withholding funds and issuing cease-and-desist orders) for schools that allow school personnel, law enforcement officers, or school security guards to subject students to corporal punishment. The bill also establishes enforcement provisions, including a private right of action for a student who has been subjected to corporal punishment. Each state educational agency (SEA) that receives federal funding must submit specified information to ED, including a school climate report that describes the SEA's policies and procedures related to exclusionary and aversive discipline practices in schools. Additionally, the bill authorizes ED to award three-year grants to SEAs and, through them, subgrants to local educational agencies to implement positive behavioral interventions and supports to address student behavior and reduce exclusionary and aversive discipline practices. ED must promulgate regulations as necessary to ensure compliance with the bill. The Department of Defense and the Department of the Interior must ensure that the schools they operate or fund also comply with these regulations.