Slovenia has become the only Nato country to appoint a woman as head of its army.
Maj Gen Alenka Ermenc will take up the post of chief of staff on Wednesday.
The 55-year-old former army commander began her military career in 1991, when the country won its independence from the former Yugoslavia.
Maj Gen Ermenc is currently serving as the army's deputy-chief of staff. President Borut Pahor said he hoped she would improve the army's performance.
"The global trend of a deteriorating security situation continues and even though Slovenia is not directly threatened military-wise, it must improve its military safety relatively quickly," he said in a statement released by his office.
Earlier this year, a Slovenian army brigade failed a Nato combat readiness test.
Maj Gen Ermenc graduated from the Royal College of Defence Studies in London and completed a Master's degree in International Studies at London's King's College University.
She will replace Maj Gen Alan Geder, who has been in post since February.
Slovenia has approximately 7.500 soldiers, including active and reserve forces.