The First Minister will speak at a press conference from her residence at Bute House in Edinburgh at 11am.
It is not yet clear if she will stand down immediately, or continue in the role until a new SNP leader is elected.
There are several possible candidates that could become the new SNP leader, such as the Deputy First Minister, John Swinney.
When Nicola Sturgeon was appointed First Minister, she appointed Mr Swinney as her deputy in 2014.
He previously served as Finance Secretary from 2007 to 2016 and the Education Secretary from 2016 to 2021.
Another potential candidate is the current Health and Social Care Secretary, Humza Yousaf.
Mr Yousaf was appointed in May 2021 and was the youngest MSP elected to the Scottish Parliament at age 26.
He has served in numerous roles and in 2018, he was was appointed as Cabinet Secretary for Justice. He introduced the Hate Crime Bill, which caused controversy among opposition parties.
Kate Forbes is also in the running. She has served as the Secretary for Finance and Economy since 2021. She was elected to Parliament in 2016 and was a convener of the Scottish Parliament’s cross-party group on Gaelic.
In 2020, following the resignation of Derek Mackay, the Cabinet Secretary for Finance and the Economy, she delivered the 2020 Scottish Budget, becoming the first woman to do so.