To reduce possible ecological impact from oil spill events, the chemical dispersant Corexit 9500A (C-9500A) is approved for widespread application. Interactions with changing environmental factors such as temperature are necessary to appropriately use dispersants in field applications, particularly in susceptible early life stages of certain marine organisms. The 24 h LC25, LC50, and LC75 values for C-9500A exposure for 3 (hours post fertilization) embryos of the teleost model Danio rerio (Hamilton, 1822) exposed to C-9500A at the standard husbandry temperature of 28.5 ˚ C were 71, 110, and 171 ppm, respectively (Probit analysis, n=5 trials of 10 individuals each). We also examined survival, early development, and hatch success of embryos and survival of larvae exposed to C-9500A while maintained at 24.7, 27.0, 29.5, and or 31.7˚ C representing both lower and higher normative thermal exposures. An interactive effect between C- 9500A and higher exposure temperature on embryo survival and hatch success was observed. Hatched larvae showed a highly reduced sensitivity to C-9500A exposure (24 h LC50 > 200 ppm), but higher variability in response than exposed embryos. We hypothesize that C-9500A application, particularly when temperatures are elevated, could negatively affect wild fish populations in nurseries and ultimately community structure.