The 1999–2000 season was Sheffield Wednesday's 133rd season in existence. They competed in the twenty-team Premiership, the top tier of English football. The club finished nineteenth and were relegated from the Premiership for the first time.
A very poor start to the season saw Sheffield Wednesday fail to win any of their first nine league games (gaining just one solitary point away to Premiership newcomers Bradford City) and an 8–0 hammering at the hands of Newcastle United in September  saw most people tip the club as favourites for relegation, and this opinion was further strengthened by their failure to make a substantial improvement as the season went on as they won just once in their first 17 games (twice in their first 20). The board of directors decided that enough was enough and on 21 March, Danny Wilson's managerial contract was terminated. Wilson's assistant Peter Shreeves took temporary charge, and kept the Owls in contention for survival right up to the penultimate day of the season. A failure to beat Arsenal confirmed their relegation after nine successive seasons of top division football, but they went down fighting by drawing 3–3 at Highbury.Bradford City manager Paul Jewell was then given the uphill task of restoring Premiership football to the club, though the club's mounting debts triggered fears that further struggles would lie ahead.