Sexual reproduction in angiosperms requires tight transcriptomic regulation in a short developmental window to guarantee double fertilization and seed production. In the last 40 years, these processes have been intensively studied, particularly at the gene expression level. Most of the studies focused on the male gametophyte because of its easier accessibility. In this chapter, we focus on insights gathered from transcriptomic studies on gametophyte development, pollen-pistil interactions, and the final steps leading to double fertilization. Since heat stress severely affects plant sexual reproduction, we briefly cover studies of its effects on gene transcription. Finally, we provide an outlook on future technological developments and how these could contribute to resolve open questions of plant sexual reproduction.