Gampaha District (Sinhala: ගම්පහ දිස්ත්‍රික්කය gampaha distrikkaya, Tamil: கம்பஹா மாவட்டம் Kampakai Māvaṭṭam) is one of the 25 districts of Sri Lanka, the second level administrative division of the country.

[4] Gampaha District is located in the west of Sri Lanka and has an area of 1,387 square kilometres (536 sq mi).

[4] The borders of the district are the Ma Oya on the north, Kelani River on the south and 1,000 ft contour line on the east.

Gampaha District is divided into 13 Divisional Secretary's Division (DS Divisions), each headed by a Divisional Secretary (previously known as an Assistant Government Agent).

[2] The majority of the population are Sinhalese, with a minority Sri Lankan Moor and Sri Lankan Tamil population.