The 31-year-old Rodríguez announced the happy news on Instagram on Monday with a photograph showing a huge ring on her finger.
"Yes, I do," read the caption in Spanish, adding "In this and in all my lives."
Rodríguez and the 40-year-old Ronaldo have two daughters together. She has also helped to raise Ronaldo's other three children. The couple lost one of their newborn twins, a boy, in 2022.
Ronaldo met Rodríguez in 2016 when she worked at a Gucci store in Madrid. The former Real Madrid and Manchester United star now plays for Al-Nassr in Saudi Arabia.