Valeris (played by Kim Cattrall), was a Vulcan navigational officer of the USS Enterprise NCC-1701-A in the fictional Star Trek universe. She appeared in the 1991 film Star Trek VI: The Undiscovered Country.

Groomed by Mr. Spock to be his successor as science officer following his pending retirement, Valeris instead becomes involved in a plot to assassinate the president of the United Federation of Planets in order to sustain hostilities between the Federation and the Klingon Empire, which is making overtures of peace. Valeris is directly involved in the assassination of Chancellor Gorkon, and once implicated, undergoes a forced mind-meld conducted by Spock which forces her to identify her fellow conspirators.

When the script for Star Trek VI was first written, the traitor was to have been Saavik, a character introduced in Star Trek II: The Wrath of Khan. Star Trek creator Gene Roddenberry requested a new character be created instead, as Saavik had become a beloved part of the Star Trek universe.