Golob's liberal party GS became the largest party by a narrow margin in the parliamentary elections in March.
It was still not enough to stay in power. Golob, who has led a center-left coalition since 2022, is now throwing in the towel after failing to garner enough support from other parties.
"We look forward to working in opposition," Golob said, according to the AFP news agency.
Instead, right-wing leader Janez Jansa is expected to have the chance to form a government again, which would be his fourth time.
67-year-old Jansa was one of Donald Trump's main allies in the EU during the US president's first term in the White House.
