The 28-year-old Swedish international’s previous contract with the Gunners was slated to end this summer.
Blackstenius has 43 goals in 83 appearances in all competitions for Arsenal, having arrived on a free transfer in January 2022 from Swedish club BK Hacken.
“In the space of two and a half years, this club has come to feel like home,” she stated.
“There is such a special atmosphere around this club and we are all hungry to achieve more together.”
Blackstenius has been Arsenal’s top scorer for the last two seasons and has twice won the FA Women’s League Cup.
Arsenal manager Jonas Eidevall described Blackstenius as a “top-class striker”.
