Section 21 may refer to:
The nurses' section of Arlington National Cemetery, a US military cemetery Section Twenty-one of the Canadian Charter of Rights and Freedoms, concerning language rights Section 21 of the Housing Act 1988 of the UK, concerning a formal notice to quit — see Section 21 notice Section 21 of the Indian Penal Code, definition of "public servant" Section 21 of the Constitution Act, 1867, Canada