Can you be a teacher with high school degree?

No, you generally cannot be a *certified* teacher with only a high school degree. Most countries require at least a bachelor's degree, and often a specialized teaching degree or certification, to teach in public schools. While there might be very limited exceptions for certain vocational or highly specialized roles, or in very informal settings (like tutoring), a high school diploma alone is not sufficient for the legal requirements of teaching in a formal school setting.