Beer was brewed on Slovene lands long before industry. The first record of brewing in Ljubljana dates from 1592, and the brewing story of Laško is traced to a hospital of 1560. Brewing declined in the 16th century, grew slowly in the 17th and rose fast after 1848; by the start of the 20th century there were about 50 breweries, among them Union, Talis and Laško. Hops came late to the Savinja valley: after failed attempts in the mid-19th century the nobleman Janez Hausenbichler planted seedlings from Germany, and Žalec became the centre of Slovene hop growing.

The two big breweries date from this time. Franz Geyer set up the first brewery in Laško in 1825 and brewed stone beer; Heinrich August Uhlich bought it in 1838 and sold beer as far as Trieste, Anton Larisch built a new plant in 1867, and Simon Kukec, who took over in 1889, became known as the father of Laško beer. In Ljubljana the children of Johann Kosler founded a brewery in 1864 beside the Vienna-Trieste railway and brewed their first beer in 1867. In 1909 it became the joint-stock company Pivovarna Union, with Vienna capital and the Graz brewers Reininghaus and Puntigam, and by 1926 it had bought a string of small breweries, Laško among them in 1924. An innkeepers' shareholder brewery set up around 1930 and the Laško pivo brand of 1938 brought Laško back. Union was nationalised in 1946, and Laško had come under the ministry of industry in 1945. Laško sold 500,000 hl a year by the early 1970s and by 1991 was the largest of 28 Yugoslav breweries; independence cost it the Yugoslav market, but it sold a million hectolitres again in 1994 and floated its shares in 1995.

In 2001 Laško and its subsidiary Radenska bought 24.99% of Union, and the Belgian Interbrew answered in October with 20%. Laško passed 50% on 10 December 2004, and on 11 February 2005 it bought Interbrew's 41.32% for EUR 70.7 million, reaching 95.17%. A management buyout led by Boško Šrot's Infond Holding (2008) failed in the crisis of 2009, and the group was restructured with 18 banks in 2014. Heineken signed for a majority of Laško on 13 April 2015 and closed on 15 October 2015, paying EUR 119.5 million for 53.43%; Laško and Union were merged as Pivovarna Laško Union in 2016.

Craft brewing began with Vizir in Črnomelj, a wine company that went into beer, and Human Fish, which started in Slovenj Gradec and moved to Vrhnika in 2012. Pelicon in Ajdovščina followed in 2013, Mali Grad in Kamnik left the garage in 2014, and Reservoir Dogs moved into its hall in Nova Gorica in 2016; Tektonik is Ljubljana's first craft brewery. In 2024 Slovenia had 96 breweries paying excise and made 1.8 million hl, including non-alcoholic beer; on 1 August 2025 the brewers' association warned that high excise duties threaten the small ones.

Union's brewing was moved from Ljubljana to Laško in 2022, after a safety check found its 35-year-old cooling system unfit (announced 26 October 2021); packaging and logistics stayed. The Zala and Sola soft-drink brands were sold in January 2023. On 14 May 2026 the company opened the City Brewery Union, a small-batch brewery inside Pivnica Union in Ljubljana. Wholly owned by Heineken, it employs more than 400 people (567 at the end of 2020) and has announced a EUR 30 million investment programme; Rok Kregar succeeds Marta Bulhak as chief executive in January 2027.