| Official Name: | Sandnessjøen |
| Settlement Type: | Town |
| Pushpin Map: | Nordland#Norway |
| Pushpin Label Position: | top |
| Pushpin Map Caption: | Location of the town |
| Subdivision Type: | Country |
| Subdivision Name: | Norway |
| Subdivision Name1: | Northern Norway |
| Subdivision Name2: | Nordland |
| Subdivision Type3: | District |
| Subdivision Name3: | Helgeland |
| Subdivision Type4: | Municipality |
| Subdivision Name4: | Alstahaug Municipality |
| Established Title: | Town status |
| Established Date: | 1999 |
| Utc Offset1: | +01:00 |
| Utc Offset1 Dst: | +02:00 |
| Area Total Km2: | 4.09 |
| Population As Of: | 2017 |
| Population Total: | 6,043 |
| Population Density Km2: | 1478 |
| Postal Code Type: | Post Code |
| Postal Code: | 8800 Sandnessjøen |
| Coordinates: | 66.0181°N 12.6159°W |
| Elevation M: | 20 |
| Elevation Footnotes: | [1] |
Sandnessjøen is a town and the administrative centre of Alstahaug Municipality in Nordland county, Norway. Sandnessjøen was granted special trading privileges in the late 1600s and it received town status in 1999. Sandnessjøen is located on the island of Alsta, just west of the De syv søstre (The Seven Sisters) mountain range.[2]
The town is a transportation hub for the Helgeland region, as well as a commercial and business centre for the region. The 4.09km2 town has a population (2017) of 6,043 which gives the town a population density of .[3]
Sandnessjøen Airport, Stokka is located south of the town. Beginning in late June 2011, the regional airline Widerøe launched direct flights in summer between Sandnessjøen Airport and Oslo Airport, Gardermoen.[4]
The town of Sandnessjøen was the administrative centre of the old municipality of Stamnes from 1899 to 1965. This municipality was also known as Sandnessjøen from 1948 until 1965. In 1965, the municipality was merged with Alstahaug Municipality.
Helgeland Kammerkor, a mixed choir with members drawn from the region of Helgeland, was founded in Sandnessjøen in 1992 and has held many concerts there.