"Must See TV" was an advertising slogan that was used by the National Broadcasting Company (NBC) to brand its prime time blocks during the 1990s, and most often applied to the network's Thursday night lineup, which featured some of its most popular sitcoms and drama series of the period, allowing the network to dominate prime time ratings on Thursday nights in the 1980s and 1990s. Ratings for NBC's lineup fell during the mid-to-late 2000s. In 2015, the network canceled comedy programming on Thursdays and switched entirely to dramas. In popular culture, the phrase is most strongly associated with the network's entire Thursday night lineup, including both sitcoms and dramas, which dominated the ratings from the 1980s through the late 1990s.
"Must See TV" originally applied to sitcoms (dramas would normally be promoted separately), and for much of the 1990s the phrase was used several nights a week as an attempt at brand extension. At one point in the fall of 1997, the brand was used five nights a week, with four sitcoms a night from Monday to Thursday, and two on Sunday. NBC itself would later adopt the more common interpretation; the 2002 retrospective, 20 Years of Must See TV, focused on NBC's overall dominance on Thursday nights from 1982 onward, and overlooked extensions such as "Must See TV Tuesday."