The Borg were originally conceived as being a race of insects (as featured in the previous season's Conspiracy (1988)). Budget restrictions meant that the decision was made to go with cyborgs instead. Nevertheless, Q Who still went $50,000 over budget. Insectoid races would appear as enemies in the subsequent series Star Trek: Voyager (1995) and Star Trek: Enterprise (2001).
This is the episode in which the Borg make their debut. They would eventually go on to become this series' ultimate nemesis (an honour originally meant for the Ferengi, but never materialised since fans took them as "too comical" for this role; later on, the Cardassians became the big bad, a threat more advanced than the major 3, and then, when trying to control the wormhole, the Dominion came in; more advanced than the major 3 but beatable; the Borg had to be used sparingly to avoid any unbelievability about them as a superpower). Originally, they were not intended to have a queen, and the two-part episode in which they appear later, The Best of Both Worlds: Part 1 (1990)/The Best of Both Worlds: Part 2 (1990), reflects this. The Borg Queen was created because the writers were having difficulty in writing dialogue for what was intended to be the Borg's central computer. The Borg Queen first appears in Star Trek: First Contact (1996), and queens would make several appearances through the later seasons of Star Trek: Voyager (1995).
The episode won 2 Emmy Awards for Outstanding Sound Mixing for a Drama Series and Outstanding Sound Editing for a Series.
In the observation lounge, for the only time during the series, the outline of the viewscreen behind Picard blinks red alert during the first senior staff conference.
The aliens who infiltrated Starfleet in Conspiracy (1988) (as well as the starbases disappearing in the following episode The Neutral Zone (1988)) were both originally to be part of the whole Borg storyline. However, once the writers and producers worked out what the Borg were, the tie to the aliens was dropped, though the disappearing starbases plot element was retained. This was revealed in the text commentary on the fan pick Borg DVD set.