An increase in global mean temperature leads to a substantial increase in the magnitude, frequency and duration of extreme high-temperature events, which result in profound impacts on organisms and ecosystems. Previous studies on the effects of climate warming on insect populations mainly focus on the changes in temperature means, rather than in temperature extremes. This consequently overestimates the positive effects of increases in mean temperature by neglecting the potential negative impacts of temperature extremes in nature. Here we reviewed the research progress on the impact of extreme high temperature on geographical distribution, demographic parameters and population growth, behavior, and interspecific interactions of insect populations. Temperature extremes inhibit insects in thermal limits and safety thermal range, and consequently determine the geographical distribution of insects across latitudes, altitudes and landscapes. Extreme high temperatures depress insect development, survival, and reproduction by immediate impacts and ecological consequences, thus alter demographic parameters and population growth. Extreme high temperatures can alter important life parameters by affecting various behaviors such as thermoregulation, feeding, and dispersal. The species-specific responses to extreme high temperatures may lead to changes in interspecific interactions, including relative dominance, community structure and food web, and consequently alter trophic cascades and ecosystem functioning. Previous works concerning the effects of extreme high temperatures mainly focus on the daytime temperature extremes and heat waves in summer. Since global climate change leads to asymmetric increases in temperature among different seasons, more attention should be paid to the impacts of relative temperature extremes in spring, autumn and winter in the future climate change studies.