The Belize Defence Force (BDF) is the military of Belize, and is responsible for protecting the sovereignty of the country. The BDF is under the Ministry of National Defence and Border Security, which is currently headed by Hon. Florencio Marin Jr.; the BDF itself is commanded by Brigadier General Azariel Loria. In 2012, the Belizean government spent about $17 million on the military, constituting 1.08% of the country's gross domestic product (GDP).

The military of Belize dates back to 1817, when the Prince Regent Royal Honduras Militia, a volunteer organization, was founded.

Between 1817 and 1978, the military force in Belize has had ten different names:

The Prince Regent's Royal Militia (1817-1866)
The Belize Volunteer Force (1866-1868)
The Belize Volunteer Corps (1868-1883)
The Belize Light Infantry Volunteer Force (1897-1905)
British Honduras Volunteers (1905-1916)
British Honduras Territorial Force (1916-1928)
British Honduras Defence Force (1928-1944)
British Honduras Home Guard (1942-1943)
British Honduras Volunteer Guard (1943-1973)
Belize Volunteer Guard (1973-1977)
The BDF was founded in 1978 following the disbanding of the Belize Volunteer Guard and the Police Special Force the year before.

After Belize achieved independence in 1981 the United Kingdom maintained the deterrent British Forces Belize in the country to protect it from invasion by Guatemala. During the 1980s this included a battalion and No. 1417 Flight RAF of Harriers. The main British force left in 1994, three years after Guatemala recognised Belizean independence, but the United Kingdom maintained a training presence via the British Army Training and Support Unit Belize (BATSUB) and 25 Flight AAC until 2011 when the last British Forces left Ladyville Barracks, with the exception of seconded advisers. The BDF Maritime Wing became part of the Belize Coast Guard Service in November 2005.

On October 15, 2011, the BDF changed their issued military uniforms from American-based to digital versions since October due to concerns that criminals can easily acquire them.

In October 2015, due to rising tensions between Belize and Guatemala and the British cutback on military bases worldwide to focus on the War On Terror in 2011, Belize asked the UK to bring BATSUB back; the British Government brought BATSUB to Belize once again.