BrightonGreen members voted 1,022 to 813 to call Zionism racism.
The first major UK party to do so also backs one democratic state across historic Palestine.
The UN General Assembly passed the same finding in 1975 by 72 to 35, and revoked it 111 to 25 in 1991.
Four of its five MPs opposed it, and Israel banned leader Zack Polanski, who is Jewish, from entering.
Polanski faces voters Tuesday in the by-election for Keir Starmer’s former London seat.
How each outlet framed it
drawn from 150+ reports worldwide
- Middle East Eye
- foregrounds internal Green Party fracture: Co-Deputy Leader Ali backs motion while 4 of 5 MPs oppose it
- Al Jazeera Online
- traces Zionism to Herzl's late-19th-century proposal for Jewish homeland in Palestine or Argentina amid European persecution
Sources: Middle East Eye, Al Jazeera Online