Add the greek yogurt, milk, orange juice, and banana to a large, high-speed blender. Then add the frozen pineapple and mango chunks on top
Cover and blend until smooth. This smoothie is very thick and only good blenders will be able to make it. To thin it out you can add some more orange juice or milk until it blends smooth.
Pour into glasses and serve immediately.
I used plain yogurt, but you can add more sweetness or additional flavor by substituting a tropical-flavored or vanilla Greek yogurt.
I buy pre-frozen fruit because the stays in separate smaller chunks and it's more convenient. If you prefer to use fresh fruit, you'll need about 1/2 - 1 pineapple and 1-2 mangoes depending on the size.