Municipality Šoštanj, which is part of the Savinjska statistical region, measures 96 km2; this ranks it 74th among Slovene municipalities.

Statistical data for 2011 reveal the following:

In the middle of 2011 about 8,750 people (about 4,500 men and 4,250 women) were living in the municipality, which ranks Šoštanj 58th among Slovene municipalities. The population density was 92 people per square kilometre, which was lower than the national average of 101 people per square kilometre.

The number of live births was higher than the number of deaths, which means that natural increase per 1,000 population in the municipality was positive. It was 0.1 (in Slovenia 1.6). The number of people who moved from the municipality was lower than the number of people who moved into the municipality, so net migration per 1,000 population in the municipality was positive. It was 11.2. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 11.3 (in Slovenia 2.6).

The mean age of people in Šoštanj was 41.0 years, which was lower than the national average (41.8).

As in most Slovene municipalities, in Šoštanj the number of old people was higher than the number of young people: there were 104 people, aged 65 or more, per 100 people aged 0–14. This ratio shows that the value of the ageing index was lower than the national average of 117. It also shows that the mean age of people in Šoštanj is growing more slowly than in Slovenia as a whole. Data by sex show that the ageing index for women was in all Slovene municipalities higher than the ageing index for men. In Šoštanj – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was exactly the opposite.

Šoštanj had 6 kindergartens. They were attended by 352 children or 73% of all children aged 1–5, which was less than the national average of 76%. In the school year 2011/2012 basic schools in Šoštanj were attended by about 750 pupils, while various upper secondary schools were attended by about 380 pupils. There were 50 students and 11 graduates per 1,000 people in the municipality; in Slovenia the averages were 51 per 1,000 and 10 per 1,000, respectively.

Among people aged 15–64 (i.e. working age population) about 60% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average of 58%.

The registered unemployment rate was 11.7%, which is less than the national average (11.8%). As in most Slovene municipalities, more women than men were unemployed.

In Šoštanj, average monthly gross earnings per person employed by legal persons were about 8% higher than the annual average of monthly earnings for Slovenia; and net earnings about 6% higher.

Every 14th person in the municipality was receiving at least one financial social assistance. In Slovenia as a whole every 24th person received at least one financial social assistance.

In 2011, there were 349 dwellings per 1,000 population. About 65% of dwellings had at least three rooms. Average size of dwellings in the municipality was 88 m2.

Every other person in Šoštanj had a car (50 passenger cars per 100 population); cars in this municipality were on average 9 years old.

In tourist accommodations in the municipality around 21,700 arrivals and 94,200 overnight stays of tourist were recorded, which is approximately 0.7% of all arrivals and 1.0% of all overnight stays of tourist in Slovenia.

In 2011, 277 kg of municipal waste per person was collected in Šoštanj, which is 75 kg less than on average in Slovenia.