The Regionalliga Südwest ('Regional League Southwest') is the fourth tier of the German football league system in the states of Hesse, Baden-Württemberg, Rhineland-Palatinate and Saarland. It is one of five leagues at this level, together with the Regionalliga Bayern, Regionalliga Nordost, Regionalliga Nord and the Regionalliga West.

The league was formed in 2012, when the clubs from the Regionalliga Süd, except those from Bavaria, were joined by the clubs of the Regionalliga West from Saarland and Rhineland-Palatinate.^[1]

The German league system had been reformed in 2008, when the 3. Liga was established and the number of regional leagues increased from two to three. A further alteration was made ahead of the 2012−13 season.^[2] This was prompted by the large number of insolvencies in the fourth tier, caused by high costs and infrastructure requirements, while the clubs at this level complained about low incomes and lack of interest from TV broadcasters. Regionalliga stadia were required to have at least 1,000 seats and a separate stand with separate entrance for away spectators, and such requirements were seen as causing excessive financial strain on amateur clubs. Many clubs also struggled to cope with the 400-page long licence application, as they had to rely on volunteers rather than being able to draw on permanent staff.^[3] This led to Oberliga champions sometimes declining their right to promotion to avoid the financial risks of the Regionalliga.^[4]

In October 2010, at a special conference of the German Football Association, the DFB, 223 of the 253 delegates voted for a reform of the league system at the fourth level. The number of Regionalligas was to be expanded to five, with the re-establishment of the Regionalliga Nordost, the formation of the Regionalliga Bayern and a shift of the Regionalliga Süd to the new Regionalliga Süd/Südwest, later renamed Regionalliga Südwest.^[1]

The suggestion for the league reform had come from Bavaria, where, in a meeting of top-level amateur clubs at Wendelstein, the financial survival of the leagues and clubs in the current system had been questioned. This meeting resulted in the publication of the Wendelsteiner Anstoß, which demanded a clear demarcation between professional football in the first three tiers of German football and amateur football below that. For this purpose, the paper demanded a re-establishment of the German amateur football championship as an incentive and goal for top amateur clubs that did not want to turn professional.^[4][5]

With the reform in 2012, the Regionalliga was increased from three to five leagues. The Regionalliga Südwest is hosted by the Southwestern Regional Football Association and the Southern German Football Association (with the exception of the Bavarian Football Association). It extends over the federal states of Rhineland-Palatinate, Saarland, Hesse and Baden-Württemberg.

Rules for promotion to the 3. Liga have changed over time (see Promotion to the 3. Liga). Typically, four teams each year are relegated to and promoted from the three Oberliga leagues below the Regionalliga Südwest: the Oberliga Rheinland-Pfalz/Saar, Hessenliga and Oberliga Baden-Württemberg.

In 2017, the league signed an agreement to host the China national under-20 football team, allowing the team to compete in the league in friendly matches to fill in as the league's 20th club.^[6] The arrangement was only approved by 16 of the 19 clubs in the league, with those in opposition criticising it as part of the increasing commercialisation of football.^[7] During the team's match against TSV Schott Mainz, the display of a Tibetan flag led to the team walking off in protest.^[8] Consequently, the Chinese players were recalled^[9] and the agreement was abrogated.^[10]

• Promoted teams in bold.
• ¹ SC Freiburg II did not apply for a 3. Liga licence and was replaced by third placed 1. FSV Mainz 05 II in the promotion round, which Mainz completed successfully.

The top goal scorers and spectator statistics for the league are:

Final league positions of all clubs who have played in the league:

• ¹ At the end of the 2013–14 season Eintracht Frankfurt decided to withdraw its reserve side from all competitions after a ruling by the DFL allowed all Bundesliga and 2. Bundesliga clubs to freely choose whether or not to operate an under-23 reserve team. Previous to that such teams had been compulsory.^[43] The team was re-established in 2022.
• ² SSV Ulm 1846 declared insolvent at the end of the 2013–14 season and was relegated.