| Rietavas Municipality | |
| Native Name: | Rietavo savivaldybė |
| Native Name Lang: | lt |
| Settlement Type: | Municipality |
| Image Map1: | RietavoRajonoSeniunijos.png |
| Map Caption1: | Map of Rietavas municipality |
| Subdivision Type: | Country |
| Subdivision Name: |  Lithuania |
| Subdivision Type1: | Ethnographic region |
| Subdivision Name1: | Samogitia |
| Subdivision Type2: | County |
| Subdivision Name2: | Telšiai County |
| Parts Style: | para |
| Parts Type: | Elderships |
| P1: | 5 |
| Seat Type: | Capital |
| Seat: | Rietavas |
| Unit Pref: | Metric |
| Area Total Km2: | 586 |
| Area Rank: | 45th |
| Population Total: | 7,381 |
| Population As Of: | 2021[1] |
| Population Rank: | 58th |
| Population Density Km2: | auto |
| Population Density Rank: | 57th |
| Timezone1: | EET |
| Utc Offset1: | +2 |
| Timezone1 Dst: | EEST |
| Utc Offset1 Dst: | +3 |
| Area Code Type: | Telephone code |
| Area Code: | 448 |
| Blank Name Sec1: | Major settlements |
| Blank Info Sec1: | Rietavas (pop. 3,234) |
Rietavas Municipality is one of 60 municipalities in Lithuania.
According to the 2021 Lithuanian census, Rietavas Municipality had the highest fertility rate in Lithuania - with an average of 2.019 children per woman, compared to the national average of just 1.506 children per woman.[2]