Cellou Dalein Diallo is a Guinean economist and politician who was Prime Minister of Guinea from 2004 to 2006. Previously he held a succession of ministerial posts in the government from 1996 to 2004. Currently he is President of the Union of Democratic Forces of Guinea (UFDG), an opposition party. He was a candidate in the 2020 Guinean presidential election but lost to incumbent Alpha Condé.

Presidential elections were held in Guinea on 18 October 2020. Incumbent president Alpha Condé was running for a third term. He was challenged by former prime minister Cellou Dalein Diallo, as well as several other candidates.