Kristi Lynn Arnold Noem (née Arnold; born November 30, 1971) is an American politician serving since 2025 as the 8th United States secretary of homeland security. A member of the Republican Party, she served from 2019 to 2025 as the 33rd governor of South Dakota and from 2011 to 2019 represented South Dakota's at-large congressional district in the U.S. House of Representatives.

Born in Watertown, South Dakota, Noem began her political career in the South Dakota House of Representatives, serving from 2007 to 2011. Noem was elected as the first female governor of South Dakota in 2018 with the endorsement of President Donald Trump. She gained national attention during the COVID-19 pandemic for opposing statewide mask mandates and advocating voluntary measures. Noem has conservative positions on most domestic issues, particularly gun rights.

Noem is a farmer, rancher, and member of the Civil Air Patrol. She has published two autobiographies, Not My First Rodeo: Lessons from the Heartland (2022) and No Going Back (2024), which sparked controversy for its account of her killing a young family dog and inaccurate claims about meeting with foreign leaders. Donald Trump nominated her for Secretary of Homeland Security in his second cabinet. She was confirmed in January 2025 by a Senate vote of 59–34.

She also shot her puppy.