Teachers from some states might be surprised to learn this, but in California, teachers do not need a master's degree. I don't have one, and I'm frozen on our pay scale until I get a master's degree (or 28 more units), but I could conceivably retire without ever having to get an advanced degree. I have a bachelor's degree and a teaching credential, and that's enough for California.
What I learned last week, though, is that school administrators in California don't need a master's degree, either. All they need is an administrative credential.
I don't know why, I just assumed that all school administrators had advanced degrees.