The Qatari Second Division (Arabic: دوري الدرجة الثانية القطري), QSD or Second Division League, also was known as Qatargas League due to sponsorship reasons, is the second tier of football league competition in Qatar. Contested by 8 teams, it operates on a system of promotion and relegation with the Qatar Stars League (QSL), the top-tier football league in the country. The QSD seasons run from September to April.
The league's first season was played in 1979 which was won by Al-Ittihad. The club with the most QSD wins is Al-Markhiya which has won 6 QSD titles. According to the league's development strategy, starting with the 2022–23 season, the first-placed club of this league will play a relegation match against the tenth-placed club of the first league to decide which club will participate in the first league next season. There is no relegation from the second division.
In 1990, the Qatar Football Association dissolved three second division clubs: Al Nasr, Al Tadamon, and Al Nahda. The clubs' players and staff were distributed to first division clubs. As a result, the Qatari Second Division was unofficially dissolved on a temporary basis. The competition resumed operations in the 1996–97 season. The first promotion play-off took place in the 1999–00 season, between Second Division champions Muaither SC and the bottom-ranked team of the Qatar Stars League, Al Shamal. Muaither lost the match.
It was announced on 15 April 2009 that no clubs would be relegated from the top flight in the 2008–09 season, due to expansion reasons, however the announcement was made with only one game remaining. This meant that the Qatari Second Division would remain with the same number of teams despite the recent formation of Lekhwiya SC and El Jaish SC, while the top flight would expand to 12 teams.
On 6 October 2013 it was announced Qatari Second Division had a sponsorship with Qatargas.
An annual competition known as the Qatari Second Division Cup is played by all second division clubs.