| Coordinates: | 57.9834°N -7.287°W |
| Location Map: | Scotland Outer Hebrides |
| Caption: | Gasker shown within the Outer Hebrides |
| Gridreference: | NA970151 |
| Official Name: | Gasker |
| Celtic Name: | Gàisgeir |
| Area: | 20frac=8NaNfrac=8 |
| Highest Elevation: | 320NaN0 |
| Population: | 0 |
| Island Group: | Harris and Lewis |
| Local Authority: | Western Isles |
| References: | [1] |
Gasker is a small uninhabited islet in the Outer Hebrides of Scotland, 8abbr=offNaNabbr=off southwest of Scarp, off the west coast of Harris.
The low-lying island has never been inhabited. In spite of its small size, it has several small pools of fresh water. It is principally noted for its large well-established seal colony. Residents of Scarp once visited Gasker regularly to kill seals for food.
There are two feasible landing spots for small craft: Geo Iar on the north side of Gasker, and Geodha Ear on the south side. A small unmanned lighthouse was built by the Northern Lighthouse Board in 1997.
1.2km (00.7miles) east-southeast lies the smaller islet of Gàisgeir Beag, and some surrounding rocks.