The official list was released on Thursday, with head coach Fernando Santos choosing his players for the UEFA Nations League matches against the Czech Republic and Spain.
Portugal are currently second in League A Group 2, boasting seven points from their four matches, one point behind leaders Spain, with the two teams set to lock horns on the final matchday.
Ronaldo, who scored his first goal of the campaign in Manchester United's 2-0 win over Sheriff Tiraspol in the Europa League on Thursday night, is a part of the squad.
Meanwhile, he is joined by Red Devils teammates Diogo Dalot and Bruno Fernandes, who were also both involved in the European clash in Moldova.
Joao Cancelo, Pepe, Ruben Dias, Ruben Neves, Bernardo Silva, Diogo Jota and Joao Felix are also among the players named in the squad for the upcoming matches.
There are notable exceptions, though, with David Carmo, Renato Sanches, Otavio, Pedro Goncalves, Goncalo Guedes and Andre Silva all missing out.
Tiago Djalo, who is yet to appear for the national team, is in the squad, while Joao Mario and Pedro Neto have also been named by head coach Santos.
The squad is arguably close to the one that the head coach will name for the 2022 World Cup, which begins in November.
Ronaldo is the captain and leading goalscorer in the squad, having found the back of the net on 117 occasions for his country, and he will once again be a key figure for his national side in the upcoming tournament.
Portugal will start their World Cup campaign against Ghana on November 24, while they will also take on Uruguay and South Korea in Group H.
Portugal squad:
Diogo Costa, Jose Sa, Rui Patricio; Danilo Pereira, Diogo Dalot, Joao Cancelo, Tiago Djalo, Pepe, Ruben Dias, Nuno Mendes, Raphael Guerreiro; Joao Palhinha, Ruben Neves, Bernardo Silva, Bruno Fernandes, Joao Mario, Matheus Nunes, Vitinha, William Carvalho; Cristiano Ronaldo, Diogo Jota, Pedro Neto, Joao Felix, Rafa Silva, Ricardo Horta, Rafael Leao