| Mosfellsbær | |
| Settlement Type: | Municipality |
| Mapsize: | 250px |
| Pushpin Map: | Iceland |
| Subdivision Type: | Country |
| Subdivision Name: | Iceland |
| Subdivision Type1: | Region |
| Subdivision Name1: | Capital Region |
| Subdivision Type2: | Constituency |
| Subdivision Name2: | Southwest Constituency |
| Leader Title: | Mayor |
| Leader Name: | Regína Ásvaldsdóttir |
| Unit Pref: | Metric |
| Area Total Km2: | 185 |
| Population Footnotes: | [1] |
| Population As Of: | 1 February 2023 |
| Population Total: | 13,430 |
| Population Density Km2: | 61.96 |
| Postal Code Type: | Postal code(s) |
| Postal Code: | 270, 271, 276 |
| Code1 Name: | Municipal number |
| Code1 Info: | 1604 |
Mosfellsbær (pronounced as /is/, colloquially Mosó) is a town in south-west Iceland, 120NaN0 east of the country's capital, Reykjavík. The coat of arms of the municipality is a tightly-knotted triquetra, a symbol often used in Celtic knotwork and strongly associated with the Celtic nations (which featured prominently in Celtic spirituality as well as Ancient Celtic religion in the past and, to some extent, to this day). The coat of arms might denote the Gaelic heritage of Mosfellsbær as Icelanders are also descended from Gaelic-speaking settlers who voyaged or were brought by the Norsemen in Iceland during the country's settlement in the Viking Age.
See also: List of twin towns and sister cities in Iceland.
Mosfellsbær is twinned with:[2]
