The controversial whistleblowing website, which hit the headlines in 2010 after publishing more than 700,000 classified US government documents, had already reached 20 percent of its target by Tuesday afternoon.
High-profile donors included Greece's former finance minister Yanis Varoufakis, fashion designer and environmental campaigner Vivienne Westwood, journalist Glenn Greenwald and WikiLeaks editor-in-chief Julian Assange.
Hundreds of demonstrations were held in April, mainly in Europe, against the Transatlantic Trade and Investment Partnership (TTIP).
"Today WikiLeaks is taking steps to ensure that Europeans can finally read the monster trade deal," it added.
"The secrecy of the TTIP casts a shadow on the future of European democracy," warned Assange.
"Under this cover, special interests are running wild. The TTIP affects the life of every European and draws Europe into long term conflict with Asia. The time for its secrecy to end is now."
If concluded, TTIP would be the world's biggest trade deal, linking about 60 percent of the globe's economic output in a colossal market of 850 million consumers, creating a free-trade corridor from Hawaii to Lithuania.
