Cllr Dore, who has led the local authority since 2011, having been elected in 2000, announced in January she would not be seeking re-election as councillor for Park & Arbourthorne when her term was due to expire in May.
However, when the local elections were cancelled due to the coronavirus pandemic, she stayed on as leader to help manage the city's response.
She said: “When I announced in January that I would not be seeking re-election in May, no one could have predicted the events that were about to unfold over the coming months.
"When the Covid crisis hit in March and the local elections were cancelled I thought it was the only right and responsible thing to do to stay on to help navigate Sheffield through the crisis.”
A new Leader of the Labour Group, which controls Sheffield City Council, will be elected on Monday, 7 December.
Cllr Dore said she was proud of the way the city has come together to support each other since the pandemic hit. She will continue to represent the Park & Arbourthorne ward until her term expires in May 2021.
Cllr Dore added: “Clearly this is still far from over and we still have much more to do to beat this. But I think that now is the right time to allow a new leader to take over, as we enter a new year and a new chief executive will also be starting in January.
“As I said when I announced I would not be seeking re-election, it has been such a great honour to serve my community as a councillor for 20 years and the city that I love as Leader of the council for nearly 10 years. I have always said that for me Sheffield is the best place in the world, I have lived here all my life, raised my family here and there is no where else I would ever want to live. I would like to thank everyone who I have worked with in this time, it is the people of Sheffield who make this city what it is and it has been a privilege to serve them.”