Greenwich Village preservationists are fighting a plan for an 18-story residential tower at Sixth Avenue and Sullivan Street, calling it another blow to the South Village’s vanishing character.

The developers are asking the city for a zoning change to build the Flatiron Building-inspired, 210-foot tower, including 27 condos, two town houses and six retail shops in a commercial zone.

But opponents, including the Greenwich Village Society for Historic Preservation, say the triangular tower would dwarf other buildings in the neighborhood.

A rep for the developer didn’t return a message left for comment.