| ZSSS | |
| Location Country: | Slovenia |
| Affiliation: | ETUC |
| Members: | 300,000 |
| Full Name: | Association of Free Trade Unions of Slovenia |
| Native Name: | Zveza svobodnih sindikatov Slovenije |
| Headquarters: | Ljubljana, Slovenia |
| Key People: | Dušan Semolič, president Milan Utroša, general secretary |
| Website: | www.sindikat-zsss.si |
The Association of Free Trade Unions of Slovenia (Slovenian: Zveza svobodnih sindikatov Slovenije) (ZSSS) is the largest national trade union center in Slovenia, with a membership of 300,000. It was formed from the remains of the old Yugoslav-era unions.
The ZSSS has control of all four of the trade union seats in the National Council of Slovenia, and is affiliated with the European Trade Union Confederation.