Preheat oven to 375 degrees F. Line a 9x5 loaf pan with parchment paper, lightly grease, and set aside.
Mix gluten-free flour, almond flour, sugar, ground flaxseeds, baking powder, cinnamon, and salt in a large bowl.
Combine mango puree, oil, and vanilla in a medium bowl and stir into the flour mixture until fully combined. Fold the diced mango into the batter.
Spread the batter into the prepared loaf pan. Bake for 60 minutes or until a toothpick inserted in the center comes out clean.
Transfer mango bread pan to a cooling rack for 10 minutes. Remove from pan and allow to completely cool before serving.