An emissary is someone who is sent on a mission as a representative of another person. In medical terminology, the word also means "Any of various venous channels through the skull that connect the venous sinuses of the dura mater with veins external to the skull" (American Heritage Stedman's Medical Dictionary).

For the Bajoran people in the fictional Star Trek universe, the Emissary is a religious figure believed to represent the Prophets; Benjamin Sisko filled this role.

"Emissary" was the first episode of Star Trek: Deep Space Nine. It is not to be confused with "The Emissary", an early episode of Star Trek: The Next Generation.