Gareth Bale and Co were bidding to be the first British team in a final since England won the World Cup in 1966.
But their fairytale run to the last four in their first major championships since 1958 was wrecked in Lyon.
Portugal, which last reached the final of the competition in 2004, will face either host nation France or world champion Germany in Paris on Sunday.
This contest had been billed as clash between two of the world's top players -- Ronaldo and his Real Madrid teammate Gareth Bale.
But Bale, who has enjoyed a stellar tournament for a country which had never before qualified for the tournament, failed to match the exploits of his rival.
Bale said: "It's very disappointing to be so close to the final but we have to be proud. This is a proud moment for us, we have achieved a lot. We had pride and passion.
Ronaldo, who equaled Michel Platini's record of scoring nine career goals at the Euros, will now hope to exorcise the ghosts of 2004 when Portugal was beaten by Greece in a final held in its own backyard.
"I hope that [after the final] we'll be smiling and that it will be tears of joy in the end," Ronaldo told the tournament's official website.
"I've always said my dream was to win a trophy with Portugal. We're closer to doing it and I believe that we'll win.
"With a lot of work, humility and the spirit of self-sacrifice, which I have always shown in my career, these sorts of things are doable."