A phenomenon that strongly influences the demography of small introduced populations and thereby potentially their genetic diversity is the demographic Allee effect, a reduction in population growth rates at small population sizes. We take a stochastic modeling approach to investigate levels of genetic diversity in populations that successfully overcame either a strong Allee effect, in which populations smaller than a certain critical size are expected to decline, or a weak Allee effect, in which the population growth rate is reduced at small sizes but not negative. Our results indicate that compared to successful populations without an Allee effect, successful populations with a strong Allee effect tend to (1) derive from larger founder population sizes and thus have a higher initial amount of genetic variation, (2) spend fewer generations at small population sizes where genetic drift is particularly strong, and (3) spend more time around the critical population size and thus experience more genetic drift there. In the case of multiple introduction events, there is an additional increase in diversity because Allee-effect populations tend to derive from a larger number of introduction events than other populations. Altogether, a strong Allee effect can either increase or decrease genetic diversity, depending on the average founder population size. By contrast, a weak Allee effect tends to decrease genetic diversity across the entire range of founder population sizes. Finally, we show that it is possible in principle to infer critical population sizes from genetic data, although this would require information from many independently introduced populations.T HE amount of genetic diversity in a recently established population is strongly shaped by its early history: While the founder population size determines the amount of genetic variation imported from the source population, the population sizes in the following generations influence how much of this variation is maintained and how much is lost through genetic drift. A phenomenon that strongly affects the early history is the demographic Allee effect, a reduction in the average per-capita growth rate in small populations (Stephens et al. 1999;Fauvergue et al. 2012). Allee effects have been detected in species from many different taxonomic groups (Kramer et al. 2009). Apart from cooperation between individuals, the study subject of the effect's eponym (Allee 1931), they can result from a variety of other mechanisms such as difficulties in finding mating partners, increased predation pressure in small populations, inbreeding depression, or biased dispersal toward large populations (Stephens et al. 1999;Kramer et al. 2009). In this study, we investigate the population genetic consequences of two kinds of demographic Allee effect: Our main focus is on the strong demographic Allee effect, in which the average per-capita growth rate is negative for populations smaller than a certain critical population size, but we also consider the weak demographic Allee eff...