Abstract: Strumigenys emmae (Emery, 1890) (Subfamily Myrmicinae, Tribe Dacetini) is a tiny predatory ant (total length ~ 1.7 mm) that feeds on minute soil arthropods. Strumigenys emmae has spread to many parts of the world through human commerce. However, because S. emmae workers are so small and slow moving, most people remain unaware of their presence. To examine the spread of S. emmae, I compiled specimen records from > 350 sites worldwide. I documented the earliest known S. emmae records for 64 geographic areas (countries, island groups, major Caribbean islands, and Us states), including many areas for which I found no previously published records: Anguilla, Antigua, Aruba, Barbados, Barbuda, Bonaire, British Virgin Islands, Cape Verde, Cayman Islands, Comoro Islands, Grenada, Îles Éparses, Jamaica, Montserrat, Palau, St Kitts, St Lucia, Tobago, and Trinidad. Strumigenys emmae appears to be originally from the Australian region, where all its closest relatives are found. Strumigenys emmae occurs primarily in tropical areas. Almost all subtropical records come from peninsular Florida, plus a few subtropical records from the Bahamas, Japan, and Australia. Strumigenys emmae is most commonly found in intact xeric and mesic forest, as well as in planted areas around buildings, but rarely occurs in moist habitats. There is little information available regarding any possible impact of S. emmae on the native mesofauna in its introduced range.