Chemical surface modifications involving 1% sodium hydroxide (NaOH) and 1% acrylic acid (AA) treatments are applied to woven banana fabric and it is used as reinforcement in an unsaturated polyester matrix. Vacuum bagging technique was used to prepare the woven banana fiber-reinforced unsaturated polyester composites with four different volume percentages of fibers (5, 10, 15, and 20%). The effects of fiber-loading and fiber surface treatments on the flexural, impact and water absorption properties of the composites were investigated. The acrylic acid treatment results in improved mechanical and water absorption properties of the composites compared to the alkali treatment and untreated fiber composites. The treatment effects on the banana fibers have been characterized by means of infrared spectroscopy (FTIR) and microscopy analysis (SEM). The moisture absorption test showed that acrylic acid-treated woven banana fabric composites exhibit less water absorption than both alkali-treated and untreated woven banana fabric composites.