"We seek your (the rebels') forgiveness in resigning today, leaving behind our responsibility as chiefs of battlefronts and (opposition) military councils," the officers said in a statement.
Their resignation comes more than three years into an anti-Assad revolt, which saw protesters take arms against the regime after the army and security forces unleashed a brutal crackdown against dissent.
Some Western military aid has trickled into Syria in recent weeks, but overall the United States has been reticent to arm rebels over fears advanced weapons could end up in jihadist hands.
Weapons shipped to Syria from the West, but more significantly from Gulf countries, are usually sent to specific groups, rather than to the Supreme Military Council, which was meant to coordinate the rebel military effort.
Lieutenant-Colonel Mohammad Abboud told AFP he and the eight other rebel officers resigned because the "SMC has no role any more. Donor countries have completely bypassed it."
Instead, donor countries have funnelled military aid, including US-made anti-tank missiles, to factions of their choosing, Abboud said.
"While we thank donor countries for their assistance, it has been really insufficient, and simply too little to win the fight," Abboud said.
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Rebels fighting Assad's regime have repeatedly urged the West to give them specialised weaponry to help tip the balance in the war against Assad's forces, which is backed by Iran, Russia and powerful Lebanese movement Hezbollah.
Earlier in June, President Barack Obama said Washington would "ramp up" support for rebels, signalling a change in US policy.
But, faced with successive military defeats around Homs and Damascus province, rebels say they lack the aid needed to change the course of the war.
"We are fighting both the army and the Islamic State of Iraq and the Levant (ISIL)," Abboud said, referring to a jihadist group operating in Syria and Iraq that Syria's opposition turned against in January.
"Yet we haven't got the help we need from countries who say they support our demands for democracy and a civil state."
ISIL has been battling a range of other rebel groups, from moderates like the FSA to Syrian Al-Qaeda affiliate Al-Nusra Front, since January.
The inter-rebel fighting is estimated to have killed 6,000 people.
On Monday, ISIL fighters spearheaded a major offensive in Iraq, seizing swathes of territory in predominantly Sunni areas and pushing towards Baghdad.