Belonolaimus is a genus of nematodes. They are known commonly as sting nematodes. They are ectoparasites that feed on plant roots, sometimes becoming agricultural pests. They are found in the United States, Mexico, and Puerto Rico. The genus was erected with the description of B. gracilis from the roots of a pine tree in Florida in the United States. Other species were soon described from various pine species. B. longicaudatus was recognized as an important agricultural pest in the southeastern United States.