Significance This study systematically identified adenosine to inosine (A-to-I) editing sites in Neurospora crassa and showed the existence of stage-specific editing events at different sexual stages. Unlike in humans, fungal A-to-I editing mainly occurred in coding regions and caused nonsynonymous changes that significantly increased proteome complexity. In general, nonsynonymous editing sites in Neurospora are adaptive and favored by positive selection. RNA editing enables stage-specific functions or expression of proteins important for different sexual developmental processes. Some editing events are well conserved and may affect genes important for other genetic and epigenetic phenomena occurring during sexual reproduction. Overall, our results provide insights into the complex regulation of sexual development and reveal the role of A-to-I editing for adaptive evolution in Neurospora.