Markus Thomas Theodor Söder (born 5 January 1967) is a German politician from Bavaria, Germany serving as Minister-President of Bavaria since 2018 and leader of the Christian Social Union in Bavaria (CSU) since 2019.

Söder was born in Nuremberg, Germany and is the son of a building contractor. After graduating from the Dürer-Gymnasium Nuremberg in 1986, Söder completed his compulsory year of military service from 1986 to 1987. He then studied law at the University of Erlangen–Nuremberg from 1987, with a scholarship from the Konrad Adenauer Foundation. He passed his first state examination in 1991 and was a research assistant at the department of constitutional, administrative and church law at the same university. In 1998, he was awarded a doctorate in law with a dissertation in legal history with the title Von altdeutschen Rechtstraditionen zu einem modernen Gemeindeedikt. Die Entwicklung der Kommunalgesetzgebung im rechtsrheinischen Bayern zwischen 1802 und 1818 (lit. 'From old German legal traditions to a modern municipal edict: The development of municipal legislation in Bavaria on the right bank of the Rhine between 1802 and 1818'). He worked as a trainee and then as an editor with Bayerischer Rundfunk, a public-service television and radio network, based in Munich, from 1992 to 1994, when he was elected to the Bavarian Parliament and became a full-time politician.

Söder has been a member of the Landtag, the state parliament of Bavaria, since 1994. From 2003 to 2007 he was secretary general of the CSU party, the sister party in Bavaria of the Christian Democratic Union of Germany (CDU). In this capacity, he worked closely with then Minister-President and party chairman Edmund Stoiber. During his time in office, he was also part of the CDU/CSU team in the negotiations with the Social Democratic Party of Germany (SPD) on a coalition agreement following the 2005 federal elections, which paved the way to the formation of Chancellor Angela Merkel's first cabinet.

Söder has since been member of the Beckstein, Seehofer I and II cabinets. From 2007 to 2008 he was Bavaria's State Minister for Federal and European Affairs, the successor office of Foreign Minister of Bavaria, and from 2008 to 2011 State Minister for Environment and Health. In the negotiations to form a coalition government following the 2009 federal elections, Söder was part of the working group on the environment, agriculture and consumer protection, led by Ilse Aigner and Michael Kauch, and the working group on health, led by Ursula von der Leyen and Philipp Rösler.

As finance minister in the state government of Minister-President Horst Seehofer, Söder was also one of the state's representatives at the Bundesrat, where he served on the Finance Committee. During his time in office, Söder was put in charge of overseeing the restructuring process of ailing state-backed lender BayernLB in a bid to win approval for an aid package from the European Commission. In 2014, he pushed BayernLB to sell its Hungarian MKB unit to that country's government, ending an ill-fated investment that had cost it a total of €2 billion ($2.7 billion) in losses over 20 years. In 2015, Söder and his Austrian counterpart Hans Jörg Schelling agreed a provisional deal that settled the two governments’ array of legal disputes stemming from the collapse of the Carinthian regional bank Hypo Alpe-Adria-Bank International. Under the memorandum of understanding, Austria would pay €1.23 billion to Bavaria. All legal cases relating to the dispute would also be dropped.

Also in 2012, Söder and Minister-President Horst Seehofer filed a lawsuit in the Federal Constitutional Court, asking the judges to back their call for an overhaul of the German system of financial transfers from wealthier states (such as Bavaria) to the country's weaker economies. On Söder's initiative, Bavaria became the first regional government in Volkswagen's home country to take legal action against the carmaker for damages caused by its emissions-test cheating scandal. At the time, Söder argued that the state's pension fund for civil servants had lost as much as €700,000 ($780,000) as a consequence of the scandal. When Seehofer came under pressure after the CSU had suffered heavy losses in the 2017 national elections, he decided to remain party chairman but agreed to hand over leadership of Bavaria to Söder. This was the result of a long-running "internal strife" between Söder and Seehofer.

In March 2018, lawmakers formally elected Söder as new Minister-President of Bavaria to replace Horst Seehofer, who had become Federal Interior Minister in Chancellor Angela Merkel's new cabinet. He received 99 of the 169 state deputies's votes, with 64 voting against – a better result than Seehofer when he began his final term in 2013.

The following Bavarian State Election (October 2018) yielded the worst result for the CSU (top candidate Markus Söder) since 1950 with 37% of votes, a decline of over ten percentage points compared to Seehofer's last result from 2013. As a consequence, Söder had to form a coalition government with the Freie Wähler as minor partner. In January 2019, CSU delegates elected Söder to replace Seehofer as their leader with an 87.4 percent majority at a party conference. He was the sole candidate.