Karl Nehammer (German: [kaʁl ˈneːhamɐ]; born 18 October 1972) is an Austrian politician who served as the 28th chancellor of Austria from 2021 to 2025. A member of the Austrian People's Party (ÖVP), he previously was Minister of the Interior from 2020 to 2021, general secretary of the ÖVP from 2018 to 2020, as well as a member of the National Council from 2017 to 2020. Nehammer assumed the chancellorship as the successor of Alexander Schallenberg, who resigned in order to return to the post of Minister of Foreign Affairs. Nehammer announced his resignation as chancellor and ÖVP leader after unsuccessful coalition talks following the 2024 legislative election. He stepped down as chancellor on 10 January 2025.

Nehammer grew up in Vienna, where he attended Kalksburg Grammar School and subsequently Amerlingstrasse Grammar School, graduating in 1992. He completed his military service as a one-year volunteer with further service until 1996. In 1997 he was discharged as a lieutenant. He then worked as an instructional trainer for information officers for the Federal Ministry of Defence and as a trainer for strategic communication for various institutions, such as the Vocational Promotion Institute (BFI) and the Political Academy of the Austrian People's Party.

From 2012, Nehammer completed a two-year university course in political communication at the University for Continuing Education Krems and graduated with a master's degree.

Nehammer is a member of the Catholic Austrian Students' Corporations Sonnberg Perchtoldsdorf within the Mittelschüler-Kartellverband.

Nehammer became active within the ÖVP party organisation after leaving the military, initially working with the party academy. He was then head of the service and mobilisation department at the party headquarters from 2007 to 2008 and the training and networking department from 2008 to 2009. He then became director of the party academy's Lower Austria association and was considered close to then-deputy governor Wolfgang Sobotka.

In October 2015, Nehammer was appointed deputy general-secretary and federal organizational speaker of the Austrian Workers' Union (ÖAAB), the trade union association of the ÖVP. During the 2016 Austrian presidential election, he was appointed replacement manager for the ÖVP's Andreas Khol partway through the campaign, but was unable to save him from a historically poor result of 11%.

He succeeded August Wöginger as general-secretary of the ÖAAB in 2016 and held this position until January 2018. In November 2016, he was also elected regional chairman of the ÖAAB Vienna. Since April 2017, he has been district party chairman of the ÖVP in Vienna-Hietzing.

In the 2017 federal election, Nehammer was elected as a representative for Vienna. During the subsequent government formation, he was a member of the ÖVP negotiating team in the area of defence. He was elected as deputy chairman of the ÖVP parliamentary faction on 8 November and was appointed media spokesman. On 25 January 2018, he succeeded Elisabeth Köstinger and Stefan Steiner as general-secretary of the ÖVP. In September 2018, he also succeeded Efgani Dönmez as spokesman for integration and migration.