Gather all your ingredients to have everything on hand and ready to go.
In your blender, combine the frozen banana, baby spinach, peanut butter, almond milk, Greek yogurt, and protein powder (if using).
Blend on high speed until all ingredients are well combined and the mixture is smooth, about 30 seconds to a minute.
If the smoothie is too thick, add more almond milk until it reaches your desired consistency and blend briefly.
Taste your smoothie. If you prefer it sweeter, add honey or another sweetener of your choice.
Pour your Green Smoothie into a glass or a travel mug and enjoy immediately for the best flavor.
