Acanthocephala declivis is a species of North American true bugs with a range from the southern United States to Guatemala and some Caribbean islands. It is the largest of this genus within this range, generally growing to be 28 to 34 mm (1.1 to 1.3 in) long. It can be distinguished from similar species by its much more broadly expanding pronotum, which extends much further than the abdomen, and the blunt tubercles on the midline of the anterior pronotal lobe, which is not present in other Acanthocephala species within its range.