Waheguru is a term most often used in Sikhism to refer to God, the Supreme Being or the creator of all.
It means "Wonderful Teacher" in the Punjabi language, but in this case is used to refer to God. Vāhi (a Middle Persian borrowing) means "wonderful" and guru (Sanskrit: guru) is a term denoting "teacher".

Waheguru is also described by some as an experience of ecstasy which is beyond all descriptions. The most common usage of the word "Waheguru" is in the greeting Sikhs use with each other:
Waheguru Ji Ka Khalsa, Waheguru Ji Ki Fateh
Wonderful Lord's Khalsa, Victory is to the Wonderful Lord.