Moscow's Basmanny District Court on Tuesday (early Wednesday AEST) ruled to arrest Yulia Navalnaya, who lives abroad, on charges of alleged involvement in an extremist group.
Navalny, the fiercest political foe of Russian President Vladimir Putin, died in February in an Arctic prison while serving a 19-year sentence on extremism charges that he condemned as politically motivated.
Authorities said he became ill after a walk but otherwise gave no details.
Navalny was imprisoned after returning to Moscow in January 2021 from Germany, where he had been recuperating from the 2020 nerve agent poisoning that he blamed on the Kremlin.
Navalnaya has accused Putin of her husband's death and vowed to continue his activities.
Russian officials have vehemently denied involvement in the poisoning and death.
Her spokesperson, Kira Yarmysh, in a post on social media platform X described the court's ruling as a recognition of Navalnaya's "merits".
