The vote paves the way for the 10,500 writers who walked off the job on November 5 to return to work on Wednesday.
Patric Verrone, the west-coast president of the WGA, said: "The strike is over."
"Our members have voted. Writers can go back to work."
Vote on contract
WGA members will vote later on the three-year contract itself, which provides new payments to writers for work streamed on the internet and doubles rates they earn for films and TV shows resold as internet downloads.
The union's board approved a deal on Sunday giving writers a share of the growing revenue from programmes offered on the internet and other new media.
Guild leaders say they were fighting for a piece of the future, reflecting the widespread belief that internet-delivered entertainment fare would inevitably claim an increasing and perhaps even dominant market share.
The strike threw the US television industry into turmoil, derailed several Hollywood movie productions and idled thousands of entertainment workers - from actors and directors to hairstylists, set designers and clerks.
The impact included more than $2bn in lost wages and earnings in the Los Angeles area alone, more than half from damage to businesses like limousine services, florists, caterers and restaurants, according the Los Angeles Economic Development Corporation.