Bookanakere Siddalingappa Yediyurappa // ^ⓘ (born 27 February 1943), commonly known as B. S. Yediyurappa or BSY, is an Indian politician from the Bharatiya Janata Party (BJP). He has served as chief minister of Karnataka for four terms and as a member of the Karnataka Legislative Assembly from 1983 to 2022, although his tenure was not continuous throughout that period.

In 2008, Yediyurappa assumed office as the chief minister of Karnataka after leading the BJP to victory in the state's legislative assembly elections, marking the first occasion on which the BJP formed a state government in south India. In 2011, he resigned after being indicted over a corruption case but was acquitted in 2016. In 2012, owing to alleged ill-treatment by the BJP high command, Yediyurappa parted ways with the party to establish his own political outfit, the Karnataka Janata Paksha (KJP). In 2014, he merged the KJP with the BJP and was subsequently elected to the 16th Lok Sabha from the Shimoga constituency. He later resigned from the Lok Sabha following his election to the Karnataka Legislative Assembly in the state election held in 2018, after which, he was sworn in as chief minister for the third time. However, he failed to secure major support in the Assembly and resigned two days later. H. D. Kumaraswamy subsequently took the oath as chief minister. In July 2019, the Kumaraswamy government lost its majority following the resignation of 17 MLAs. Yediyurappa was once again sworn in as chief minister, and in the by-elections held later that year, consolidated his majority.

Yediyurappa resigned as chief minister on 26 July 2021, on the second anniversary of his fourth term. He was succeeded by Basavaraj Bommai, on 28 July 2021.

Yediyurappa was born on 27 February 1943 in the village of Bookanakere, located in the Mandya district of the former Kingdom of Mysore, then part of British India. His parents were Siddalingappa and Puttathayamma, and the family belongs to the Banajiga sub-sect of the Lingayat caste. His mother died when he was four. He completed his pre-university college education at the Government College in Mandya, affiliated with the University of Mysore. Since his youth Yediyurappa has been affiliated with the Rashtriya Swayamsevak Sangh (RSS), a right-wing Hindu nationalist paramilitary organisation, as well as the Bharatiya Jana Sangh, a far-right Hindu nationalist political party which was the political arm of the RSS and the precursor to the BJP.

In 1965, he moved to Shikaripura where he began working as a clerk at a relative's rice mill. In 1967, Yediyurappa married Mythradevi, the daughter of a rice mill owner. He has two sons, B. Y. Raghavendra and B. Y. Vijayendra, and three daughters, Arunadevi, Padmavati and Umadevi. Mythradevi died in 2004.

In 2007, he changed the spelling of his name from "Yediyurappa" to "Yeddyurappa", following the advice of his astrologers. He later returned to the original spelling, Yediyurappa, before the oath-taking ceremony of his fourth term as chief minister of Karnataka in 2019. In 2020 and 2021, he contracted COVID-19 but recovered soon afterwards. In 2022, a 30-year-old granddaughter of Yediyurappa committed suicide.

In 1972, he was elected to the Shikaripura Town Municipality and was also appointed the president of the Taluk unit of the Jana Sangh. In 1975, he was elected President of the Town Municipality of Shikaripura. He was imprisoned during the Emergency in India and lodged in the Bellary and Shimoga jails. In 1980, he was appointed President of the Shikaripura taluk unit of the BJP and later went on to become the president of BJP's Shimoga district unit in 1985. In 1988, he became the State President of the BJP in Karnataka. He was first elected to the lower house of the Karnataka Legislature in 1983 and has since represented the Shikaripura constituency six times. Following the 1994 state assembly elections, he became Leader of Opposition in the Karnataka Legislative Assembly. In 1999, he lost the elections but was nominated by the BJP to become a member of the legislative council (upper house) of Karnataka. Again, he was re-elected in 2004 and became the Leader of Opposition in the Karnataka Legislative Assembly during the chief ministership of Dharam Singh.

During his first tenure in government, Yediyurappa supported Janata Dal (Secular) leader H. D. Kumaraswamy in bringing down the coalition government led by Dharam Singh and forming a new administration in partnership with the BJP. As part of the agreement between the JD(S) and BJP, it was decided that H. D. Kumaraswamy would serve as Chief Minister for the first 20 months, followed by Yediyurappa for the subsequent 20 months. In the Kumaraswamy-led Government, Yediyurappa held the positions of Deputy Chief Minister and Finance Minister.