南达科他州（英语：State of South Dakota）是美国中西部平原上地势较高的一州，过去曾是美国印地安人苏族中拉科他族（Lakota）的聚落所在。南达科他州在1889年11月2日加入美国联邦，也是在同一天被命名的。

南达科他州的北边是北达科他州，南边是内布拉斯加州，东边则紧邻爱荷华州与明尼苏达州，西边是怀俄明州和蒙大拿州，它同时也是美国上被称为边疆带（Frontier Strip）六州中的一州。

美国战舰南达科他号（USS South Dakota）就是以此州命名的。

该州分为66个郡，请参看南达科他州的郡列表（List of South Dakota counties）。

South Dakota (/ˌsaʊθ dəˈkoʊtə/; locally /[ˌsɑʊθ dəˈko̞ɾə]/) is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux Native American tribes. South Dakota is the 17th most extensive, but the 5th least populous and the 5th least densely populated of the 50 United States. Once the southern portion of the Dakota Territory, South Dakota became a state on November 2, 1889, simultaneously with North Dakota. Pierre is the state capital and Sioux Falls, with a population of about 165,000, is South Dakota's largest city.