Petr Fiala ([ˈpɛtr̩ ˈfɪjala]; born 1 September 1964) is a Czech politician and political scientist who has been the prime minister of the Czech Republic since November 2021 and leader of the Civic Democratic Party (ODS) since 2014. He previously served as the Minister of Education, Youth and Sports from 2012 to 2013. Prior to entering politics, he was the rector of Masaryk University.

Fiala was first elected to the Chamber of Deputies as a non-partisan in the 2013 election. He won the 2014 Civic Democratic Party leadership election, promising to reform the party and regain public trust after a corruption scandal involving Prime Minister Petr Nečas. Fiala's party finished a distant second place in the 2017 legislative election, and remained in opposition despite multiple offers from the incoming Prime Minister Andrej Babiš to participate in his governing coalition.

In 2020, Fiala led the initiative for a centre-right electoral alliance with KDU-ČSL and TOP 09, known as Spolu. He became its candidate for the premiership in the 2021 Czech legislative election, running on a pro-Western and pro-European centre-right platform, focused on fiscal responsibility and closer relations with NATO as part of Atlanticism. The alliance outperformed initial opinion polls and received the highest number of votes in the election, though with one seat fewer in the Chamber of Deputies than second-placed ANO 2011.

Under Fiala's leadership, Spolu formed a coalition agreement with the Pirates and Mayors alliance, with a majority of 108 of 200 seats. He was appointed prime minister by President Miloš Zeman on 28 November 2021 and Petr Fiala's Cabinet took power on 17 December, making him the third oldest person to hold the office, as well as the first with a political science background and the first from Brno.

Fiala came into office promising to reform and stabilize the government's growing national debt; however, the early months of his premiership saw the Russian invasion of Ukraine, the provision of aid to Ukraine, and the opening of the Czech Republic's borders to the highest number of Ukrainian refugees per capita in the ensuing Ukrainian refugee crisis. Fiala imposed sanctions on Russia and pushed to block Russian citizens from travelling to the European Union. He expressed strong support for Israel during the Gaza war. In 2022, the Czech Republic held the presidency of the Council of the European Union. Fiala's administration also faced rising inflation and resulting decline of real wages, wider concerns about the economy and the ongoing global energy crisis. Throughout his term, Fiala's government has seen approval ratings in the low 20s. He led the Spolu alliance into the 2025 election.

Petr Fiala was born in Brno to a conservative Catholic family. His father, who was partly of Jewish origin, was a Holocaust survivor. Fiala studied history and Czech language at the Faculty of Literature of Masaryk University between 1983 and 1988, and after graduating he worked as a historian in a local museum in Kroměříž.

In 1996, he became a docent at Charles University in Prague, and in 2002 he was named as the first professor of political science in the Czech Republic. In 2004, he became dean of the Faculty of Social Studies at Masaryk University, and in the same year was elected as rector of the university, defeating Jan Wechsler in the third round. Fiala was reelected in 2008 and remained in the position until 2011. While Fiala was rector, Masaryk University increased its enrollment to around 45,000 students, became the most popular Czech university in terms of applications, and created a nationwide system for detecting academic plagiarism. During this period, Masaryk University built a new €220 million campus for biomedicine, opened a research station in Antarctica, and established the Central European Institute of Technology (CEITEC) using CZK 5.3 billion from the European Structural and Investment Funds. CEITEC launched in 2011.

In the 1980s, Fiala was involved in independent civic activism. Between 1984 and 1989, he participated in the so-called underground university, hosting seminars in Brno focused on political philosophy. He was involved in unofficial Christian activities, especially in the circle of secretly consecrated Bishop Stanislav Krátký. Along with other Brno students, he founded the samizdat university magazine Revue 88, published in 1988–1989.