In a YouTube video, Navalnaya said she had drawn hope from the huge crowds that turned out last week for the funeral of her husband, who died in an Arctic penal colony on February 16, and who since then have submerged his grave in a sea of flowers.
She urged people to join the March 17 action that Navalny, Russia's best known opposition figure, had called for shortly be died.
His idea was that people could register a protest, without any risk of arrest, by all turning out en masse at the same time on election day in cities across the country.
"We need to use the election day to show that we exist and there are many of us. We are real, living people, and we are against Putin. You need to come to the voting station on the same day and at the same time - March 17 at noon," Yulia Navalnaya said.
"What to do next? The choice is yours. You can vote for any candidate except Putin. You can ruin the ballot, you can write 'Navalny' in big letters on it. And even if you don't see the point in voting at all, you can just come and stand at the polling station, and then turn around and go home."
Since her husband's death, Navalnaya has promised to continue his work and made several high-profile political appearances in the West, including meeting US President Joe Biden and addressing the Munich Security Conference and the European Parliament.
The Kremlin has strongly denied accusations by Navalnaya that Putin had Navalny killed, and has declined to comment on the public response to his death and funeral.
His death certificate said he died of natural causes at the age of 47.
