Helicotylenchus, commonly known as spiral nematodes, belong to the family Hoplolaimidae. Members of this genus are considered plant-parasitic nematodes but only become economically significant at over 1000 individuals per plant. These nematodes are distributed worldwide; however, the countries where the Helicotylenchus are reported vary depending on the species. However, many studies have been done on various spiral nematodes, such as H. dihystera. A reduction of above-ground development was observed in olives infected with H. dihystera with over 1000 nematodes per plant. Helicotylenchus species are polyphagous with a diverse range of plant species as hosts. Most Helicotylenchus are ectoparasite; however, semi-endoparasite has also been observed for this nematode. These nematodes cause necrosis on the infected roots and a patchy symptom on the fields where Helicotylenchus attack the plants. The life cycle in Helicotylenchus varies among the species, but in H. multicinctus associated with bananas, the life cycle was completed in 39 days. Species identification in this taxon based on morphology is challenging due to the overlap of the characteristics. Therefore, DNA barcoding is used as a helpful tool. Different means to manage Helicotylenchus have been used. Thus, in this chapter, various aspects of Helicotyelnchus are discussed.