The following is excerpted from the most recent edition of the American Philological Association's Careers for Classicists in Today's World.
Certification (also called "licensure" or "getting credentialed") is the official "license to teach," and is granted by individual states. It is among the first things prospective employers look for in a candidate. It has been said that private schools put less emphasis on certification and are more willing to hire uncertified teachers. This is less true today than it has been in the past. In recent times, in the face of state and federal accountability programs such as "No Child Left Behind," a credentialed teacher is very desirable to private schools. Moreover, if certification is postponed, a teacher can find it hard to move from a private school to a public school. Given the mobility of today's population, relocation is common; so, being credentialed is vital. For all these reasons, it is very desirable to pursue state certification as early as possible in your career. There are sometimes scholarships available to help defray the cost of getting certified.
Every state has its own rules for awarding certification. As early as possible, contact your school's education department and/or the state board of education to obtain a copy of your state's guidelines. The Education Committee of the American Philological Association has created a page with links to each state's requirements.
Always check with the state's own web page on teacher certification to be sure you are reading the most up-to-date rules, since they tend to change frequently.
Each college or university has its own procedures as well. In some colleges you will have to major in education. In others you may major in Latin or Classics. Be sure to check as soon as possible and be aware that colleges and universities differ in that some only offer certification at the BA level, while others only at the MA level.
It is not uncommon for Latin positions to appear that require the ability to teach another subject either as a major or a minor part of your teaching load. As a prospective teacher you may want to acquire a second field of competence and the requisite certification to teach it. Some powerful second fields include another foreign language, mathematics, English, and history. Note that often a teacher need not be certified in the field that comprises the minority of his/her teaching load. However, again, make the proper inquiries.
Several states have alternative paths to certification. Such plans are often ideal for Classics majors who have decided to pursue a teaching career mid-way through their college careers. Each state differs and not all states have such programs. Some states also have advanced certificate programs for MA and PhD holders. Contact the placement officer of your institution's Education department for particulars and search the web page of any state's Department of Education for all the rules surrounding certification.
In some cases it will be profitable to go on to advanced study before entering the teaching profession. There are several ways to do this. If you graduate from college already certified to teach, you may wish to pursue a regular Master's Degree (MA) in Latin or the Classics. This will enhance your knowledge of the subject and is quite practical since most school systems, public and private alike, have a higher pay scale for teachers with a Master's. Some states require the MA for permanent certification, though in some this degree may be obtained in a field such as Education. If, however, you are not certified, but have an undergraduate major in Latin or the Classics, there are two paths to consider. The first is a Master of Arts in Teaching Degree (MAT) or its equivalent. After completing such a degree, a candidate not only has a Master's Degree but is also certified to teach Latin. In such programs students take both Classics courses and pedagogical courses. All involve at least one teaching experience in a K-12 setting under supervision. This is generally called the "practicum" or "student teaching." An alternate route may also exist to certification. Many schools of Education offer an intensive certification program that begins directly following graduation with the BA. Check with your own institution to see if your Classics major can fit into such a program.