Nine species of marasmioid fungi are described from material collected in the Hawaiian islands: Marasmiellus pacificus, Marasmius pseudobambusinus var. hawaiiensis, and Marasmius radiatus are described as new; Marasmius sp. is described provisionally; Gloiocephala epiphylla, Marasmiellus mesosporus, and Marasmius androsaceus are first reports for the Hawaiian Islands; Marasmius sphaerodermus and Tetrapyrgos nigripes are redescribed based on Hawaiian specimens. Most taxa are illustrated and compared with phenetically similar taxa. This brings the total number of agarics reported from the Hawaiian Islands to 101 taxa, 23% of which are marasmioid fungi. Key words: Agaricales, Hawaiian Islands, marasmioid fungi.