Merton Council has already granted the All-England Club permission to create an 8,000-seater stadium and courts in Wimbledon Park.
But Wandsworth is responsible for the northern part of the park and unanimously rejected the proposal.
Wimbledon CEO Sally Bolton says they are “disappointed” by the decision.
The plans will now be referred to the Mayor of London’s office.
Iain Simpson, Chair Save Wimbledon Park (SWP) said, “This result is very heartening. The councillors unanimously recognised the crucial point that this application provides no justification for so much harm to Metropolitan Open Land, our precious Green Belt.
We have nothing against the tennis. However, protecting the environment, a desire shared by the GLA and all Londoners and indeed the whole country, and keeping open space truly public for the recreation and well being of real local communities is much more important. As yet we have won nothing. In sporting parlance, we move into the next round of the competition, pleased that points we have been making for over two years have finally been acknowledged by politicians. The next step is for the GLA to prevent any further damage to the environment and such important Open Spaces.”