Municipality Ljubljana, which is part of the Osrednjeslovenska statistical region, measures 275 km2; this ranks it 11th among Slovene municipalities.

Statistical data for 2020 reveal the following:

In the middle of 2020 about 294,050 people (about 143,390 men and 150,660 women) were living in the municipality, which ranks Ljubljana 1st among Slovene municipalities. The population density was 1.069 people per square kilometre, which was higher than the national average of 104 people per square kilometre.

The number of live births was lower than the number of deaths, which means that natural increase per 1,000 population in the municipality was negative. It was -0.4 (in Slovenia -2.5). The number of people who moved from the municipality was higher than the number of people who moved into the municipality, so net migration per 1,000 population in the municipality was negative. It was -1.9. The sum of natural increase and net migration per 1,000 population in the municipality was negative. It was -2.4 (in Slovenia 6.2).

The mean age of people in Ljubljana was 42.6 years, which was lower than the national average (43.6).

As in most Slovene municipalities, in Ljubljana the number of old people was higher than the number of young people: there were 136 people, aged 65 or more, per 100 people aged 0–14. This ratio shows that the value of the ageing index was the same as the national average of 136. It also shows that the mean age of people in Ljubljana is growing as fast as in Slovenia as a whole. Data by sex show that the ageing index for women was in all municipalities except in three (Dobrovnik/Dobronak, Jezersko in Loški Potok) higher than the ageing index for men. In Ljubljana – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was the same.

Ljubljana had 128 kindergartens, which were attended by 13,347 children. Of all children in the municipality aged 1–5, 86% were included in kindergartens, which was more than national average of 81%. In the school year 2020/21 elementary schools in Ljubljana were attended by about 26,580 pupils, while various upper secondary schools were attended by about 8,610 pupils. There were 37 students and 7 graduates per 1,000 people in the municipality; in Slovenia the averages were 39 per 1,000 and 7 per 1,000, respectively.

Among people aged 15–64 (i.e. working age population) about 65% were persons in employment (i.e. persons in paid employment or self-employed persons), which is less than the national average (66%).

In Ljubljana, average monthly gross earnings per person employed by legal persons were about 16% higher than the annual average of monthly earnings for Slovenia; net earnings were about 14% higher.

Among 1,000 inhabitants in the municipality, 517 had a passenger car. The car was on average 10 years old.

In 2020, 394 kg of municipal waste per person was collected in Ljubljana, which is 39 kg more than on average in Slovenia.