Replacement names are proposed for 40 unresolved junior species group homonyms in Formicidae (Hymenoptera) as required by ICZN Articles 23 and 60. This effort aims to enhance taxonomic stability and facilitate digital management for ant names. In each case, the junior homonym is considered acceptable and in use. To avoid the creation of unnecessary replacement names, names were not proposed for unresolved junior homonyms in cases where 1) the status of the junior homonym is a junior or senior synonym or unidentifiable; 2) the primary homonym pair have not been regarded as congeneric since 1899; or 3) the congeneric placement of the junior secondary homonym is unreliable. The following new names are introduced to replace existing homonyms: Acromyrmex aurinanom. nov., Camponotus chuckinom. nov., Camponotus dorexnom. nov., Camponotus durnyxnom. nov., Camponotites flarexnom. nov., Camponotus robecchii clynenom. nov., Camponotus substitutus cylrixnom. nov., Colobopsis brevanom. nov., Crematogaster scutellaris gynianom. nov., Dolichoderus thoracicus jexinanom. nov., Ectomomyrmex pylixynom. nov., Ectomomyrmex pylornom. nov., Euponera tynaranom. nov., Formica lavateri lioranom. nov., Formica mytaranom. nov., Hypoponera rylinnom. nov., Hypoponera veltannom. nov., Lepisiota vynianom. nov., Temnothorax flavispinus noviranom. nov., Messor minor nubinanom. nov., Messor nuvianom. nov., Pheidole arnoldi qindranom. nov., Pseudoneoponera sublaevis quorranom. nov., Strumigenys wylixanom. nov., Camponotus foleyi cybiranom. nov., Camponotus maculatus brexylnom. nov., Camponotus nixranom. nov., Camponotus planus brinanom. nov., Carebara dazianom. nov., Carebara xyneranom. nov., Colobopsis vitrea yeviranom. nov., Formica dravennom. nov., Messor draxilnom. nov., Pheidole singaporensis zolaranom. nov., Pseudolasius zynianom. nov., Tetramorium drunexnom. nov., Tetramorium fenixnom. nov., Tetramorium flinexnom. nov., Temnothorax fynornom. nov., and Tetraponera vantixnom. nov. In addition, Estevianom. nov. is proposed for the preoccupied genus Wilsonia Hong, 2002. Additional taxonomic changes are presented, including the reinstatement of Tetramorium schultzei Forel, 1910a stat. nov. and the following new combinations: Bothroponera jonesii (Forel, 1891), comb. nov.; Diacamma unicolor (Smith, 1860a), comb. nov.; Pseudoneoponera vidua (Smith, 1857), and Diacamma solitaria (Smith, 1860b), comb. nov.