The current paper presents new data on the nomenclature and distribution of Chalcididae (Hymenoptera, Chalcidoidea) collected in various regions of Iran. The following new synonymies are proposed: Brachymeria argenteopilosa (Radoszkowski, 1876) = Chalcis persica Masi, 1824 syn. nov., Brachymeria albicrus (Klug, 1834) = Chalcis rufigaster Masi, 1924 syn. nov. and Bucekia differens (Boucek, 1949) = B. Bouceki Nikol'skaya, 1960 syn. nov. The status of Lasiochalcidia [described under Euchalcis] igiliensis (Masi, 1916) is resurrected and is removed from synonymy with L. pubescens (Klug). Lectotypes are designated for Chalcis kassalensis Kirby, 1886, Halticella subelongata Kohl, 1906 and Chalcis pubescens Klug, 1834. Two genera, Bucekia Steffan, 1951 and Euchalcis Dufour, 1861, as well as eight species, Brachymeria kassalensis (Kirby, 1886), Dirhinus anthracia Walker, 1846, Antrocephalus subelongatus (Kohl, 1906), Bucekia differens (Boucek, 1949), Euchalcis unicolor (Lucas, 1871), L. rubripes (Kieffer, 1899), Psilochalcis dentata (Steffan, 1951) and P. subdola (Nikol'skaya, 1960), are new records for the Iranian insect fauna. A new host is recorded for E. unicolor. A list of 68 species in 18 genera of Chalcididae known from Iran is also included and some previous erroneous records are discussed.