Morales, 46, triumphed in October elections to succeed Otto Pérez Molina, who had to stand down as president the month before when he became engulfed in a corruption scandal that sparked street protests.
Leaders of several Central American countries, the Dominican Republic, Mexico, Colombia, Ecuador and Spain have also been invited to attend the ceremony at which Morales will formally take office.
The former comic won fame on television for playing a country bumpkin who nearly becomes president, but has no previous real-life experience of elected office.
He fronts the conservative FCN-Nacion party, a group founded by former military officers including some accused of committing atrocities during Guatemala’s 1966-1996 civil war. The party holds only 11 seats in the 158-seat Congress.
Political analysts and Morales himself attributed his win to public disgust with established politicians, whose reputation for graft deepened after an April report by a U.N.-backed anti-corruption commission that led to Pérez Molina’s downfall.
The United States has allocated $750 million in aid for three Central American countries savaged by gang violence, poverty and corruption: Guatemala, Honduras and El Salvador.
The money aims, in part, to stem a flood of migrants from those countries seeking to get to the relative safety and prosperity of the United States.