| Köyliö | |
| Official Name: | Finnish: Köyliön kunta Swedish: Kjulo kommun |
| Other Name: | Kjulo |
| Settlement Type: | Former municipality |
| Mapsize: | 150px |
| Pushpin Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Name: | Finland |
| Subdivision Type1: | Region |
| Subdivision Name1: | Satakunta |
| Subdivision Type2: | Sub-region |
| Subdivision Name2: | Rauma sub-region |
| Leader Title: | Municipal manager |
| Leader Name: | Seppo Saarinen |
| Established Title: | Charter |
| Established Date: | 1870 |
| Extinct Title: | Consolidated |
| Extinct Date: | 2016 |
| Area Footnotes: | [1] |
| Area Total Km2: | 259.27 |
| Area Land Km2: | 246.06 |
| Area Water Km2: | 13.21 |
| Population As Of: | 2015-06-30 |
| Population Footnotes: | [2] |
| Population Total: | 2665 |
| Population Density Km2: | auto |
| Demographics1 Info1: | % (official) |
| Demographics1 Info2: | % |
| Demographics1 Info3: | % |
| Demographics1 Info4: | % |
| Demographics2 Title1: | 0 to 14 |
| Demographics2 Info1: | % |
| Demographics2 Title2: | 15 to 64 |
| Demographics2 Info2: | % |
| Demographics2 Title3: | 65 or older |
| Demographics2 Info3: | % |
| Timezone: | EET |
| Utc Offset: | +2 |
| Timezone Dst: | EEST |
| Utc Offset Dst: | +3 |
| Coordinates: | 61.1186°N 22.3075°W |
| Postal Code Type: | Postal code |
| Website: | www.koylio.fi |
Köyliö (pronounced as /fi/; sv|Kjulo) is a former municipality of Finland. It was merged to the municipality of Säkylä on 1 January 2016.[3]
It was located in the Satakunta region. The population of Köyliö was (30 June 2015) and covered a land area of . The population density was .
The municipality was unilingually Finnish.
It is said that the peasant Lalli murdered the English bishop Henry on the ice of Lake Köyliö in 1156 AD, during the first Swedish Crusade into Finland. A statue to Lalli was erected at Köyliö in 1989.
Before the 2016 consolidation, Köyliö was twinned with;