Aim Urbanization is one of the most significant anthropogenic alterations of the surface of the Earth and constitutes a major threat to biodiversity at the global level. Arthropods are a very diverse group of organisms, with many species that provide essential ecosystem services. However, their response to urbanization is still unclear. Here, we describe the first meta‐analysis to evaluate the overall effects of urbanization on terrestrial arthropod communities and driving factors related to cities, arthropods and methods. Location Global. Time period 1979–2019. Major taxa studied Arthropods. Methods We compiled a dataset of 162 publications that have evaluated the effects of urbanization along rural–urban gradients, which yielded 196 observations for diversity and 148 for abundance of arthropods. Moderator variables related to cities (climatic region, size, age, air pollution level and vegetation cover), arthropods (taxonomic and functional group and mobility level) and methods (study duration and type of gradient) were considered. We analysed the data through a hierarchical meta‐analysis that allowed us to take into account the dependence of multiple effect sizes obtained from one study. Results Overall, urbanization had a negative effect on the diversity and abundance of terrestrial arthropods. The magnitude of the changes in diversity and abundance along the urban gradient depended on the arthropod taxonomic group. Coleoptera and Lepidoptera were the most affected groups, suggesting that not all species respond in the same way to urbanization. In addition, the age of the cities had a slightly negative influence, but only on abundance. Main conclusions Our results indicate that terrestrial arthropod communities are less diverse and abundant in more urbanized landscapes. Considering the current biodiversity crisis and the fact that urbanization is one of the most extreme forms of global environmental change, the evidence presented here could be useful to support and direct new conservation efforts in urban habitats.

1. Urbanisation is one of the main land-use changes behind global insect collapse. Despite that previous studies have described the negative effects of urbanisation on insect communities, so far there is no synthesis that considers multiple urban drivers, their combined effects, and the role of species traits altogether.2. Here we developed an integrative framework of the underlying mechanisms behind terrestrial insect species loss in cities by exploring five leading drivers: impervious surfaces, habitat fragmentation, urban heat island, pollution, and exotic plants. For each driver, we identified the main direct and indirect (mediated through species interactions or changes in resources) effects on insect populations and communities, emphasising the role of species traits as moderators of such effects.3. Body size, mobility, and oviposition/nesting requirements were the traits that frequently defined insect vulnerability to urban drivers. Urban heat island and pollution deserve further research from a community-level approach. Direct effects of drivers dominated the literature, while most indirect paths were mediated by changes in resources rather than species interactions.4. In conclusion, our review showed the challenges of recognising particular effects and mechanisms for each urban driver and their combined effects. By doing so, we intended to encourage researchers to address some of the gaps we noticed in order to fully understand how urbanisation is affecting insect communities. Finally, we outlined the main recent urban planning strategies and future challenges in order to successfully conserve urban insect biodiversity.