El Ghazi was named in Danny Blind's preliminary 28-man Netherlands squad for October's Euro 2016 qualifiers against Kazakhstan and Czech Republic.
The 20-year-old, who has scored seven goals for Ajax this season, was eligible to represent Morocco due to his parents having hailed from the North African nation.
However, El Ghazi was persuaded by Portugal captain and three-time Ballon d'Or winner Ronaldo to opt for Netherlands, who he has represented at youth level.
"I have thought about it for a long time. My parents, my family, my personal trainer and also Cristiano Ronaldo have advised me. I have included everything in my choice," El Ghazi told Ajax's official website.
"It came up with Ronaldo. He asked how I stood on the Netherlands. He said if he were me, he would opt for the Netherlands. He said I had to decide it myself and that people always have an opinion.
"Choose Netherlands and Moroccans will say I'm not a real Moroccan, opt for Morocco then the Dutch say 'Hey, you're born and raised here, what the hell is that?'
"I'm going to do my best. I'm going to give everything for the country because I was born and raised here."
Netherlands face Kazakhstan in Group A action on October 10 before tackling the already-qualified Czech Republic three days later.