It'll depend on the exact aspect of theology. In general you'll want to have a PHD in the exact discipline of theology you want to teach.
He had a master's degree from Cambridge University and studied mathematics and theology. Almost immediately after his graduation, Cambridge appointed him professor of mathematics.
Theology is not that popular a degree for a wide variety of reasons. For one, you cannot really find well-paying job after college if you major in theology unfortunately.
If you are teaching classes at a university, you will have to get your degree. If you are starting your own classes, you do not really need any certification.
To teach special education within the public school system, you must have a bachelor's degree in an education program and state teachers certification. This will take four years to complete as a full-time student, and provided you take the degree as prescribed by the college or university.
A University may award you a Batchelor's degree.
With a degree in theological studies, you will be able to get a job working with a church or other religious affiliation. Theology is the study of religion.
Astronomy
You have to know what you are going to teach. There are no education requirements. Your particular organization may require specific criteria be met before you are authorized to teach.
Bond Paper
Theology schools offer degrees of many areas, theological degrees mostly. Inquire a school of specific relevancy to learn which degrees they offer and how to obtain enrollment.
Jeff Kinney received a degree in computer science from the University of Maryland.
You will need a PhD for a start.