Global wildlife populations are in decline, in part, due to habitat loss resulting from urbanization. Urban green roofs may mitigate such habitat loss by providing supplemental habitat for wildlife, including bats, which are more active over urban green roofs than nearby traditional roofs. To better understand bat activity over urban green roofs, we surveyed bats and arthropods on a 27,316-m² green roof planted with Sedum spp. in New York City from June to August 2017. We found that Lasiurus borealis (Eastern Red Bat), a species with a diet consisting mainly of moths, accounted for 88% of identified bat calls. We collected over 15,000 arthropods of 16 taxa and found that moth abundance, while a relatively small proportion of green roof arthropods, correlated positively with bat activity. Our findings suggest that urban green roofs provide useable habitat for moths and other arthropods and, consequently, bats may forage on green roofs when prey are available.