Over 99% of the share capital approved the deal, which is set to combine the two manufacturers in to a world-leading €10 billion company.
The resulting company will have an installed-base of approximately 70GW and a €21 billion backlog, Gamesa CEO Ignacio Martin said in a presentation to shareholders in Spain.
Gamesa will "absorb" Siemens' assets in exchange for new shares, resulting in Siemens owning 59% of the new company. Gamesa will hold 41%, 8% of which will be owned by Spanish developer and utility Iberdrola.
The Spanish OEM's shareholders will also be paid a cash dividend of €3.591 per share following the closing of the merger. This is slightly lower than the €3.75 per share put forward when the agreement was announced in June.
"The transaction is not just good for Gamesa, it opens up new horizons for all of our stakeholders. By combining these two highly complementary businesses we will achieve greater geographic reach, a broader portfolio of products, services and solutions and more robust financial solidity," Martin said.
Gamesa will now seek approvals from market regulators and anti-trust authorities. The transaction is due to close by the end of Q1 2017.
The two companies announced they had reached a merger deal in June after months of negotiations.
Currently, Gamesa's offshore unit Adwen, acquired from joint venture partner Areva in September, will form part of the new company but it is expected a third-party buyer will be found.