All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It seems that the school celebrates 'Teacher's Day' which is celebrated in March, if it is the matter then it is an innovation and the Prophet said: "Whoever introduces into this matter of ours [Islam] that which is not a part of it, it will be rejected." [Al-Bukhari and Muslim]
'Teacher's Day' is like 'New Year's Day', 'Mother's Day' and 'Tree's Day', these are the days glorified and celebrated by non-Muslims. Celebrating these days is just celebrating birthday, 'Nayroz' (Persian New Year's Day) and the others days which are not approved in Islam.
Therefore, exchanging gifts in this day is not allowed to avoid imitating non-Muslims.
However, honoring teachers at any time of the year other than this day without having link with 'Teacher's Day' is allowed.
Allaah Knows best.