Reproductive development in sexual plants is substantially more sensitive to high temperature stress than vegetative development, resulting in negative implications for food and fiber production under the moderate temperature increases projected to result from global climate change. High temperature exposure either during early pollen development or during the progamic phase of pollen development will negatively impact pollen performance and reproductive output; both phases of pollen development are considered exceptionally sensitive to moderate heat stress. However, moderately elevated temperatures either before or during the progamic phase can limit fertilization by negatively impacting important pollen pistil interactions required for successful pollen tube growth toward the ovules. This minireview identifies the impacts of heat stress on pollen-pistil interactions and sexual reproduction in angiosperms. A special emphasis is placed on the biochemical response of the pistil to moderately high temperature and the resultant influence on in vivo pollen performance and fertilization.