She will face the winner of the Republican primary, which is currently too close to call.
Before running for Congress, she served in the Arizona state legislature. Sinema was elected to the State Senate in 2010, and prior to that, she served in the State House from 2005 to 2010.
“Kyrsten is a proven leader who stands up for what’s right and knows how to get results,” said Chuck Wolfe, president and CEO of the Victory Fund, which endorsed Sinema.
“We’re extremely proud of her hard-fought victory tonight and committed to helping bring her authentic voice for LGBT equality to Capitol Hill in November,” said Wolfe.
Sinema is one of eight out candidates running for Congress this year, potentially doubling LGBT representation in Washington from the current four.