Diplomats and international officials are discussing a "New Deal" for Somalia, which should see hundreds of millions of dollars pledged for the country after two decades of conflict.
The European Union (EU)-backed conference is being held in Brussels.
Al-Qaeda-linked al-Shabab dismissed the meeting as "Belgian waffle".
Al-Shabab is fighting to oust Somali President Hassan Sheikh Mohamud's government, the first to be recognised by the US in more than 20 years.
The group controls most of southern Somalia, but it has been driven out of the main cities and towns, including the capital Mogadishu, by an African Union (AU) force backing the government.
'Emergency to recovery'
BBC Somalia analyst Mary Harper says the New Deal will focus on promoting peace and state-building.
The EU and Somali government believe now is a good time to adopt the programme as the country has entered a new era, with a more legitimate government and progress on the security front, our correspondent says.
Mr Mohamud told the BBC Somali service he welcomed the proposed New Deal.
"It's a standard deal throughout the world in the post-conflict environment. This is a deal that is based on Somalia-led initiatives," he said.
The UK's ambassador to Somalia, Neil Wigan, said the conference was "a major milestone", AFP news agency reports.
Diplomats were hoping to see more than $1bn (£600,000) in pledges to help rebuild Somalia, widely regarded as a failed state with little infrastructure, it reports.
"Our combined efforts will maintain momentum and deliver the change that the people of Somalia desperately need," Mr Wigan is quoted as saying.
Al-Shabab said it expected donor pledges would remain mostly unfulfilled or the money would be lost in corruption.
"It's a bit like Belgian Waffles: sweet on the outside but really has not much substance to it," it said on its Twitter account.
Mr Mohamud said at a news conference that aid money had been used to save lives, and provide basic services to Somalis.
The New Deal would take Somalia from an "emergency to recovery" over the next three years, he said.
"This is a new chapter. Today we are ending a journey and starting a new one," Mr Mohamud added.
The EU gave Somalia about $1.6bn in aid from 2008 to 2013, AFP reports.
Most of the money was used to finance the AU force of some 18,000 troops, it reports.
Our correspondent says billions of dollars have been thrown at a problem that refuses to go away.
Somali news leader