Edited by Ulf-Ingo Fl€ uggeTrichoderma reesei is used to produce saccharifying enzyme cocktails for biofuels. There is limited understanding of the transcription factors (TFs) that regulate genes involved in release and catabolism of L-arabinose and D-galactose, as the main TF XYR1 is only partially involved. Here, the T. reesei ortholog of ARA1 from Pyricularia oryzae that regulates L-arabinose releasing and catabolic genes was deleted and characterized by growth profiling and transcriptomics along with a xyr1 mutant and xyr1/ara1 double mutant. Our results show that in addition to the L-arabinose-related role, T. reesei ARA1 is essential for expression of D-galactose releasing and catabolic genes, while XYR1 is not involved in this process.