This table is based on the minimum standards. Some courses may have higher criteria.

English proficiency 
https://graduate.mahidol.ac.th/thai/current-students/?g=6

MU GRAD TEST
http://www.grad.mahidol.ac.th/grad/mutest/index.php?module=ScheduleList.php&Type=G

TOEFL ITP
http://www.grad.mahidol.ac.th/grad/mutest/index.php?module=ScheduleList.php&Type=D

Short Courses
http://www.grad.mahidol.ac.th/engshortcourse/index.php?page=Application.php

GRID Courses
https://graduate.mahidol.ac.th/thai/current-students/?g=6&t=4