Thirty-four new species in the plant bug genus Orthotylus are described from the Hawaiian IsIands. The new species and their host plant associations are as follows: O. metrosideri, from Hawaii, on Metrosideros polymorpha; O. nestegiae, from Hawaii, on Nestegis sandwicensis; O. sophorae, from Hawaii, on Sophora chrysophylla; O. sophoroides, from Maui, on Sophora chrysophylla; O. perrottetiae, from Kauai, on Perrottetia sandwicensis; O. perrottetiopsis, from Maui, on Perrottetia sandwicensis; O. antidesmae, from Hawaii, on Antidesma platyphyllum; O. melicopi, from Hawaii, on Melicope hawaiiensis; O. coprosmopsis, from Hawaii, on Coprosma menziesii; O. coprosmicola, from Molokai, on Coprosma foliosa; O. coprosmaphila, from Maui, on Coprosma montana; O. pilo, from Molokai, on Coprosma foliosa; O. hedyotiella, from Oahu, on Hedyotis acuminata; O. hedyotivorus, from Oahu, on Hedyotis terminalis; O. hedyotioides, from Maui, on Hedyotis terminalis; O. hedyotiphila, from Maui, on Hedyotis hillebrandii; O. kara, from Oahu, on Psychotria kaduana; O. kopiko, from Maui, on Psychotria mariniana; O. neopsychotriae, from Hawaii, on Psychotria hawaiiensis; O. neopsychotrioides, from Maui, on Psychotria mariniana; O. diospyropsis, from Oahu, on Diospyros hillebrandii; O. diospyricola, from Molokai, on Diospyros sandwicensis; O. diospyroides, from Maui, on Diospyros sandwicensis; O. xylosmoides, from Maui, on Xylosma hawaiiense; O. xylosmicola, from Kauai, on Xylosma hawaiiense; O. clermonticola, from Maui, on Clermontia grandiflora; O. clermontioides, from Maui, on Clermontia arborescens and Clermontia kakeana; O. clermontiella, from Oahu, on Clermontia kakeana; O. pisoniopsis, from Maui, on Pisonia brunoniana; O. urericola, from Hawaii, on Urera glabra; O. urer