The Front for the Liberation of Occupied South Yemen (FLOSY; Arabic: جبهة تحرير جنوب اليمن المحتل, romanized: jabhat taḥrīr janūb al-Yaman al-muḥtali) was an Arab nationalist military organization operating in the Federation of South Arabia (a British protectorate; now Southern Yemen) in the 1960s.

The FLOSY attempted to seize power when the British left from another military group operating in South Arabia, the National Liberation Front (NLF).

They attempted to grant independence to the Federation of South Arabia by giving Abdullah al Asnag control of the country.

[2] In 1965 the British suspended the Federation of South Arabian government and imposed direct colonial rule.

[2] By February 1967 the British could no longer control or protect its bases in Aden and announced it was leaving the country, against American wishes.

With the loss of Egyptian support, the NLF allied with Yemen's Federal army, allowing them to defeat FLOSY.