Alojz "Lojze" Peterle (born 5 July 1948) is a Slovenian politician. He is a member of New Slovenia, part of the European People's Party. He served as Prime Minister of Slovenia from 1990 to 1992, Leader of the Christian Democrats from the founding of the party in 1990 until it merged with the Slovenian People's Party in 2000, and was Minister of Foreign Affairs from 1993 to 1994 and again in 2000. He was a Member of the National Assembly from 1996 to 2004, and a Member of the European Parliament from 2004 to 2019.

Lojze Peterle was born to a peasant family in the Lower Carniolan village of Čužnja Vas near Trebnje. He attended the Novo Mesto Grammar School. In 1967, he enrolled in the University of Ljubljana, where he studied history and geography, and later also economy. During his student years, he started collaborating with the Christian left intellectual circle around the journal Revija 2000.

In the 1980s, Peterle started working at the Institute for Urban Planning of the Socialist Republic of Slovenia. In the mid-1980s, he was involved in several projects of trans-regional cooperation within the Alpe-Adria regional cooperation network.

In 1990, he was elected president of the newly founded Slovene Christian Democrats.

Peterle became prime minister of Slovenia in May 1990 after parliamentary elections of April 1990 won by the DEMOS coalition (which included Christian Democrats and was created in the opposition to the Communist rule). In 1991, the DEMOS-led Slovene Parliament declared the country's independence from Yugoslavia, in compliance with the result of a referendum held in December the previous year. He served as prime minister until May 1992, when due to an internal crisis in the DEMOS coalition, a new coalition government under Janez Drnovšek was established by a constructive vote of no confidence. In the elections of 1992, the Christian Democrats gained some support and became the second largest party in a highly fragmented National Assembly, after the Liberal Democratic Party. The Christian Democrats entered a cross-party coalition with the Liberal Democrats and the United List of Social Democrats (former Communist Party of Slovenia) under the leadership of Janez Drnovšek.

Peterle served as deputy prime minister and foreign minister from January 1993 until October 1994. Tensions were deep in the coalition, however, and Peterle resigned from his posts in 1994 when Drnovšek nominated Jožef Školč, a member of his own Liberal Democratic Party, to be speaker of Parliament, against the wishes of Peterle who believed that a Christian Democrat should be the speaker. The Christian Democrats did remain in the coalition, which was often divided over specific policy issues. In 1996, Peterle called for the dismissal of foreign minister Zoran Thaler because of his belief that Thaler did not do enough to help Slovenia's relations with Italy.

In the 1996 elections, Peterle's party suffered a decisive defeat, losing popular support to the other two centre-right parties, the Social Democratic Party of Slovenia and the Slovene People's Party, that had remained in the opposition and had criticised what they called a "unprincipled coalition between Christian Democracy and former Communists".

Between 1996 and 2000, the Christian Democrats remained in opposition, and Peterle's leadership was frequently challenged by different fractions within the party. He nevertheless managed to remain the chairman of the Party until 2000, when the Christian Democrats merged with the Slovenian People's Party, which had until then supported Janez Drnovšek's third term as prime minister. As a consequence, Drnovšek's government fell in 2000, and Peterle became foreign minister again in the short-lived centre-right government of Andrej Bajuk from June 2000 to November 2000.