Garmsir (Pashto: ګرمسير; from Persian گرمسیر, meaning "hot place") is the center of Garmsir District in Helmand Province, Afghanistan. It is situated on the eastern bank of the Helmand River on 31°07′00″N 64°12′00″E / 31.1167°N 64.2000°E / 31.1167; 64.2000 at 714 m altitude and 63 km southwest of Lashkargah. The major road at Garmsir is Route 605. The hospital is called Hazar Juft Comprehensive Health Clinic.

Prince Harry spent time in the village during his 2008 period in the country.

Garmsir has a hot desert climate (Köppen BWh), characterised by little precipitation and high variation between summer and winter temperatures. The average temperature in Garmsir is 21.3 °C, while the annual precipitation averages 83 mm. July is the hottest month of the year with an average temperature of 33.8 °C. The coldest month January has an average temperature of 8.6 °C.

Garmsir was the scene of heavy fighting during April–September 2008 when U.S. Marines from the 24th MEU arrived to reinforce British and Afghan forces.

In July 2009, Marines taking part in Operation Khanjar met little or no resistance initially. By July 5, elements of the 2nd Battalion, 8th Marines were engaged in heavy fighting with Taliban forces.

• Muhammad bin Bakhtiyar Khalji, founder of the Khalji dynasty of Bengal (1204–1227)

• Camp Dwyer
• Forward Operating Base Delhi
• JTAC Cornet Harry Wales
• Mullah Abdul Karim (Guantanamo detainee 520)
• Helmand Province campaign

• Helmand Province

• Widow Six Seven 28 February 2008
• Taliban: We Knew About Prince Newsweek 1 March 2008
• Marines launch assault in Afghanistan MSNBC 29 April 2008
• US Marines, British forces in major new Afghan operation AFP 29 April 2008