Artificial light at night (hereafter ‘ALAN’) affects 88% of the land area in Europe and almost half of the land area in the US, with even rural areas exposed to lights from agricultural and industrial buildings. We know little about the impacts of ALAN on wildlife behavior and physiology, yet altered energy expenditure or stress physiology during the breeding period could reduce reproductive success and have conservation implications. Here, we experimentally exposed adult female and nestling tree swallows (Tachycineta bicolor) to ALAN. We then measured the effects of ALAN or control conditions on parental behavior (provisioning rate), nestling physiology (corticosterone levels), and reproductive success (proportion of eggs hatched and nestlings fledged). Our results showed that ALAN-exposed nestlings had slightly reduced baseline and increased stress-induced corticosterone, compared to control nestlings. ALAN-exposed nestlings also showed greater down-regulation in circulating corticosterone (i.e. negative feedback). Additionally, ALAN-exposed females provisioned their nestlings less frequently. Finally, ALAN was negatively associated with the proportion of eggs hatched, but not the proportion of nestlings fledged. While our results suggest a modest effect of ALAN exposure on behavior and physiology, and possible effects on hatching success, these changes did not translate to differences in fledging success. Therefore, ALAN exposure may not affect population health in this species.