Gayla B.
Patrice, It depends on how you define "classroom." In most US states, the answer is probably "no" as the various state departments of education and their teacher certification bureaus have specific academic and/or experiential requirements. (You can do an Internet search of teacher qualifications for whichever states interest you.) If you are asking about teaching in a Chinese classroom, the answer is "probably," and depends on the school's requirements. I am teaching at an American high school program and am the only certified teacher among us. The others have TEFL certificates and teaching experiences elsewhere (adult ed, corporate training, etc.). Surprisingly, colleges and universities are more lenient than lower level schools, but they also pay considerably less. Just check on the ads of places that interest you and see.

Michel D.
Even though you have a TEFL, most postings require you to have a degree. If the TEFL is online some schools won't accept it.

Dr. Muhammad S.
If you teach online independently (on your own), there are no formal requirements. You just would need to be a good teacher to keep students. Online companies may require some formal qualifications like a degree and/or a TEFL cert.. But you should be careful with them as they often fail to pay you.