President Ali Bongo is seeking a third seven-year term in office to extend his family’s 56-year grip on power.
Poling stations opened across the Central African country at 8am (07:00 GMT) on Saturday with 19 candidates on the presidential ballot, although six of the main opposition parties have backed a joint nominee to narrow the race to unseat Bongo.
Vote counting will start after polls close at 6pm (17:00 GMT). It is not yet clear when preliminary results will be announced.
The vote is a much-anticipated test of support for Bongo, who has served two seven-year terms. Detractors say he has done too little to funnel Gabon’s oil wealth towards the third of its 2.3 million population living in poverty and question his fitness to govern after a stroke in 2018.
Bongo, 64, has sought to disprove this image on a wide-ranging campaign trail. He has promised to create more jobs, boost micro-loan programmes, and cut public school fees.
The run-up to the ballot has been smooth, but many fear the post-election period could see unrest like the protests that broke out after Bongo’s 2016 victory. The opposition has disrupted both his previous election wins, saying he won fraudulently.
Recent changes to the voting system could further complicate the aftermath, said Remadji Hoinathy, a researcher at the Africa-focused Institute for Security Studies. These include the introduction of a single ballot that requires voters to pick a presidential candidate and politician from the same party.
The changes “might add more tensions on the outcome of the elections, and then maybe contestations and maybe violence,” Hoinathy said.
Bongo’s camp has positioned him as the firm favourite to win the race, although there has been no reliable polling.
His main threat comes from joint opposition candidate Albert Ondo Ossa, 69, an economics and management professor who has campaigned on the need for change and better economic opportunities.
The pitch could resonate in a country where a third of young people are unemployed and the vast majority of the population has only known Bongo’s rule.
On Friday, large crowds attended the final rallies of Bongo and Ondo Ossa in the capital, Libreville.
“I am 67 years old, I can tell you that I have never seen such enthusiasm for a candidate. I am convinced that this year there will be changeover in Gabon”, said pensioner Alain Moussavou at the opposition rally.