MEXICO CITY—President Daniel Ortega of Nicaragua easily won a third consecutive term, in a race members of the opposition and many Nicaraguans consider to be an electoral farce.

Mr. Ortega, a 70-year-old former Marxist guerrilla leader whose government has become increasingly authoritarian while embracing market-friendly economic policies, took 72.5% of Sunday’s vote with nearly all ballots counted, according to the country’s electoral council. Five little-known candidates split the rest of the vote.

Mr....