Shorebirds (Order Charadriiformes) exhibit a wide variety of breeding systems, and have been the subject of extensive studies on the evolution of these systems. Nevertheless, there are many monogamous species within this clade. Previous studies of Charadrius vociferus (Killdeer) have shown that they are monogamous, with only a single documented variation (serial polyandry). We report observations at a nest that contained 7 eggs (typical nests have 4 eggs). The nest was being attended by 3 adults, and it successfully fledged young. This is the first documented Killdeer nest with possible simultaneous polygamy.