Smoothie was formulated from banana, cucumber, and turmeric with an extreme vertices mixture design, and its physicochemical, antioxidant, and sensory properties were determined using standard methods. The properties were subjected to modelling followed by validation of the models by using relevant indices: determination (R2), average absolute deviation (AAD), bias factor (Bf), and accuracy factor (Af), and then optimized. The coefficients of determination were between 0.62 and 0.87, average absolute deviation values were near zero, and bias and accuracy factors were almost 1. While banana and cucumber increased total soluble solids and titratable acidity, turmeric increased the pH of the smoothie. Only turmeric had an increasing effect on the antioxidant properties of the smoothie. Meanwhile, all the components of the smoothie enhanced the sensory properties. The proportion of banana, cucumber, and turmeric in the optimized formulation was 0.62, 0.30, and 0.08, respectively. The models showed the capability of adequately predicting the properties of the smoothie, as demonstrated by the values of indices for validation. The smoothie could be a functional beverage with enhanced properties, especially antioxidant properties. Further research is needed to ensure the shelf stability of the formulated smoothie for commercialization, wide distribution, and marketing.