The candidacy aims "to continue the national liberation struggle," Saied said in a video on the presidency's Facebook page.
The opposition parties, many of whose leaders are in prison, have accused Saied's government of exerting pressure on the judiciary to crack down on his rivals in the 2024 elections and pave the way for him to win a second term, Reuters reported.
The re-election bid was announced the same day a court jailed opposition leader Lotfi Mraihi, a potential presidential election candidate, to eight months in prison on a charge of vote buying.
The court also banned Mraihi, leader of the Republican Union Party and one of the most prominent critics of President Kais Saied, from running in presidential elections for life.
The opposition says fair and credible elections cannot be held unless imprisoned politicians are released and the media is allowed to do its job without pressure from the government.
Saied, who was elected in 2019, dissolved parliament in 2021 and began ruling by decree in a move the opposition has described as a coup.
The president said his steps were legal and necessary to end years of rampant corruption among the political elite.