"Elementary, Dear Data" is the third episode of the second season of the American science fiction television series Star Trek: The Next Generation, the 29th episode overall. It was written by Brian Alan Lane and directed by Rob Bowman. It was originally released on December 5, 1988, in broadcast syndication.

The second season of the American science fiction television series Star Trek: The Next Generation commenced airing in broadcast syndication in the United States on November 21, 1988, and concluded on July 17, 1989, after airing 22 episodes. Set in the 24th century, the series follows the adventures of the crew of the Starfleet starship Enterprise-D. Season two featured changes to the main cast, following the departure of Gates McFadden. Diana Muldaur was cast as Dr. Katherine Pulaski for a single season before the return of McFadden in season three. Academy Award winner Whoopi Goldberg also joined the cast after pursuing a role from the producers.