Harku is a small borough in Harku Parish, Harju County, in northern Estonia. It lies within the Harjumaa region, the county that surrounds and includes the capital, Tallinn.
According to the 2011 census, the settlement had a population of 868. Of that total, Estonians numbered 539, or 62.1 percent of residents.
Harku serves as the administrative centre of Harku Parish, a municipality in Harju County. The borough is one of several small settlements in the parish, which occupies the area immediately west and southwest of Tallinn.