Under the Engineers Act B.E. 2542 (1999), the regulated professional engineer is classified into 4 classes of professional license as follows;
1) Senior Professional Engineer
2) Professional Engineer
3) Associate Engineer (Engineering-in-Training)
4) Adjunct Engineer
Each of professional licenses is limited by scope of regulated field of engineering profession work in accordance with COET Regulation on Qualification and Criteria for each level of professional license.