ABSTRACTIn this paper, we classify the minimal surfaces of general type with χ = 5, K2 = 9 whose canonical map is composed with an involution. We obtain 6 families, whose dimensions in the moduli space are 28, 27, 33, 32, 31, and 32, respectively. Among them, the family of surfaces having a genus 2 fibration forms an irreducible component of .