To examine the ecological and evolutionary impact of global climate change on animals, many studies have assessed the relationship between temperature and performance of the diploid (usually adult) stage. Fewer studies have focused on how high temperature could reduce reproductive success by effecting gamete performance. In this study, we tested for impacts of warm temperatures on sperm of the brown anole, Anolis sagrei. We measured sperm motility after sperm were exposed to temperatures from 28 to 50°C for 2 to 60 minutes. We found that both temperature and time affected sperm motility, with the sharpest declines after exposure to 43.9 °C or higher. To elucidate the effect of mild but longer-term heat, we separated sperm samples into 2 groups exposed to 28 or 33°C for 24 hours. We found that sperm motility decreased significantly more in the 33 °C compare to the 28 °C treatment. Overall, our result suggest that both sperm longevity and motility are highly effected by temperature and further study is required to elucidate the effect of warmer temperature on overall fertility.