This chapter connects long-standing anthropological fieldwork on mosquito control in West Africa with an analysis of the recent arrival of so-called invasive mosquitoes in Germany. By discussing mosquitoes in West Africa and invasive mosquitoes in Western Europe, we develop an analysis of mosquito–human–entanglements as “infrastructuring environments.” Such infrastructuring emphasizes the entangled and co-constitutive character of how mosquitoes and humans define each other and so co-create specific bio-social and environmental effects. This chapter thus approaches both the agency of humans aiming to control mosquitoes and the agency of mosquitoes creating new habitats for themselves by moving and mutating, as generative of particular human–mosquito landscapes. It demonstrates how a focus on infrastructuring allows us to bring contradictory and ambivalent concerns in health and ecology into conversation and tension with each other.