Insufficient physical activity and poor sleep have been independently associated with increased risk for reduced physical and mental health. Previous research suggests that depression is associated with both long- and short-sleep duration. Although long-sleep, defined as sleeping more than 9 hours per night, may be appropriate for young adults, those recovering from sleep debt, and individuals with illnesses, less is known about the risks of long-sleep in the general population. The objective of this study was to investigate whether physical activity moderates the relationship between sleep quantity and depression. A cross-sectional, nationally representative sample from the 2015-2016 National Health and Nutrition Examination Survey (NHANES) was used. Total metabolic equivalent (METs) scores derived from the Global Physical Activity Questionnaire (GPAQ) assessed physical activity. Self-reported Patient Health Questionnaire-9 (PHQ-9) was used to classify depression severity. Sleep quantity was calculated from self-reported sleep and wake times, rounded to the nearest half hour. Analyses revealed that meeting physical activity recommendations of 150 moderate-to-vigorous minutes per week was related to lower depression scores regardless of the quantity of sleep obtained; however, the largest effect was shown in those who over sleep. For individuals who over sleep (>9 hours), those who met physical activity recommendations were less depressed than those who do not (F(2, 5) = 4.19, p = .015).These findings suggest that health benefits of extended sleep may be enhanced when sufficient amounts of physical activity are met.