Keiko O'Brien is a character in the fictional Star Trek universe, played by actress Rosalind Chao. Introduced in 1991, she is the civilian spouse of Starfleet crew member Miles O'Brien (played by Colm Meaney) appearing occasionally in later seasons of the series Star Trek: The Next Generation (1987–1994), and more frequently as a supporting character throughout Star Trek: Deep Space Nine (1993–1999), as well as in related media such as novels. The producers wanted her as a regular character on Deep Space Nine, but Chao was only available part-time.