Preheat oven to 350°F (175°C) and grease a 9x5-inch loaf pan with non-stick spray or parchment paper.
In a large mixing bowl, combine the mashed bananas, Greek yogurt, eggs, honey, and vanilla extract; whisk until the mixture is uniform.
In a separate medium bowl, whisk together the whole wheat flour, baking soda, baking powder, salt, and cinnamon.
Gradually fold the dry ingredients into the wet ingredients using a rubber spatula until just combined, ensuring no dry flour pockets remain while avoiding over-mixing.
Transfer the batter to the prepared loaf pan and smooth the top with a spatula.
Bake for 50 to 55 minutes, or until a wooden skewer inserted into the center of the loaf comes out clean or with just a few moist crumbs.
Remove from the oven and allow the bread to cool in the pan for 15 minutes before transferring to a wire rack to cool completely before slicing.