A filter includes first and second signal terminals, a filter circuit connected between the first and second signal terminals, a substrate having first and second surfaces, the first and second signal terminals being located on the first surface, a part of the filter circuit being located at a side of the second surface, a line located closer to the first surface than the filter circuit in the substrate, a first end of the line being connected to one of the first and second signal terminals, and a ground terminal that is located on the first surface and to which a second end of the line is connected, an area of a region where the line overlaps with the ground terminal being greater than an area of a region where the line overlaps with the one of the first and second signal terminals when the substrate is viewed in plan view.