This study aimed to evaluate the recovery of polyphenols from pretreated banana peels by ultrasound-assisted extraction (UAE). The effects of temperature (40–60 °C) and ethanol concentration (40–80%) were investigated. First, the peels were pretreated with ethanol and ultrasound for 10 min to preserve the bioactive compounds during drying. The optimum extraction condition defined by the composite desirability was 52.30 °C and 60.10%, resulting in the maximum polyphenols recovery (355.11 ± 4.99 μgGAE g−1). These values were achieved by considering a short extraction time (5 min). The study also showed that UAE recovers higher levels of polyphenols and flavonoids than conventional extraction techniques (Soxhlet and hydrodistillation). In general, with eco-friendly solvents and pretreated samples, the UAE can recover significant amounts of bioactive compounds in short run times, providing a viable option for using this waste.