An acoustic wave device includes: a first substrate that includes a first acoustic wave filter located on an upper surface of the first substrate; a second substrate that is flip-chip mounted on the upper surface of the first substrate through a bump, and includes a second acoustic wave filter on a lower surface of the second substrate, the lower surface of the second substrate facing the upper surface of the first substrate across an air gap; and a shield electrode that is supported by the upper surface of the first substrate, and is located between at least a part of the first acoustic wave filter and at least a part of the second acoustic wave filter through the air gap.