The filamentous fungiTrichoderma reeseiis one of the most well-studied cellulolytic microorganisms. It is the most important fungus for the industrial production of enzymes to biomass deconstruction being widely used in the biotechnology industry, mainly in the production of biofuels. Here, we performed an analytic review of the holocellulolytic system presented byT. reeseias well as the transcriptional and signaling mechanisms involved with holocellulase expression in this fungus. We also discuss new perspectives about control of secretion and cellulase expression based on RNA-seq and functional characterization data ofT. reeseigrowth in different carbon sources, which comprise glucose, cellulose, sophorose, and sugarcane bagasse.