As currently recognised, Laelius Ashmead contains 47 known species worldwide and is found on all continents except Australia (until this study). In this paper, we examined the taxonomic limits of this genus and tested whether species of the genera Laelius and Prolaelius Kieffer constitute a monophyletic group. We also tested whether the junior synonyms Allepyris Kieffer and Paralaelius Kieffer are supported by cladistic analyses. Our initial analysis indicated that these genera form a single clade. Cladistic analyses were based on 108 female structural characters. The data set was analyzed under equal-weights parsimony and implied weighting. In both analyses, Laelius was retrieved as a polyphyletic group because Prolaelius Kieffer was always nested within Laelius and Allepyris berlandi Benoit always remained in the outgroup and was retrieved as the sister group of Disepyris sp. Based on our analyses, we propose nine nomenclatural acts and recognise 52 valid species of Laelius. The following four new species are described: Laelius haplos sp.n. and L. quadrangulus sp.n. from Australia and L. ogmos sp.n. and L. titanokkos sp.n. from ailand. The following new generic synonym is proposed: Prolaelius Kieffer syn.n. of Laelius Ashmead. The following three new combinations are proposed: Disepyris berlandi (Benoit) comb.n. from Laelius, Laelius firmipennis (Cameron) comb.n. and Laelius glossinae (Turner & Waterston) comb.n. from Prolaelius. Additionally, a lectotype is designated for Laelius fulvipes Kieffer.