Ekiti is among eight of Nigeria's 36 states where governorship elections are not being held at the same time as the rest of the country because of legal challenges to previous results.
It is also considered a swing state, key to winning presidential elections in the multi-ethnic West African country of some 200 million people.
Although 16 parties are on Saturday's ballot paper in Ekiti, it is seen as a three-horse race between Biodun Oyebanji of the ruling APC, Bisi Kolawole of PDP and Segun Oni of the Social Democratic Party (SDP).
President Muhammadu Buhari of the All Progressives Congress came to power in 2015 and his victory after three unsuccessful bids was in part the result of the southwest's support.
The 79-year-old will be stepping down after completing his two terms in office allowed by the constitution.
Two political veterans are vying to replace him -- ex-Lagos governor Bola Ahmed Tinubu of the APC and former vice president Atiku Abubakar of the People's Democratic Party (PDP) -- as well as other candidates.
Africa's most populous nation is scheduled to hold its presidential election on February 25, 2023.
Analysts say the emergence of Tinubu as the APC's presidential flagbearer has upped the stakes and changed the permutations in the Ekiti election.